It is proposed that this filing will become effective (check appropriate box):

[x] Immediately upon filing pursuant to paragraph (b)

[ ] On [date] pursuant to paragraph (b)

[ ] 60 days after filing pursuant to paragraph (a)

[ ] On [date] pursuant to paragraph (a)(1)

[ ] 75 days after filing pursuant to paragraph (a)(2)

[ ] On [date] pursuant to paragraph (a)(2) of Rule 485

If appropriate, check the following box:

[ ] This post-effective amendment designates a new effective date for a previously filed post-effective amendment.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereto duly authorized, in the City of Santa Fe and State of New Mexico on February 13, 2013.

The Registrant represents that this post-effective amendment no. 87 (i) is filed solely for one or more of the purposes specified in paragraph (b)(1) of Rule 485 under the Securities Act of 1933 and
that no material event requiring disclosure in the prospectuses filed herein (other than one listed in paragraph (b)(1)(i)) has occurred since the latest date specified in paragraph (b)(2) of Rule 485, and (ii) meets all of the requirements for
effectiveness under paragraph (b) of Rule 485.

THORNBURG INVESTMENT TRUST

Registrant

By

*

Brian J. McMahon, President

Pursuant to the requirements of the Securities Act of 1933, this Registration Statement has been signed
below by the following persons in the capacities and on the date indicated.

EX-101.INS
2
tit4-20130129.xml
XBRL INSTANCE DOCUMENT
0000816153tit4:S000000540Member2012-02-022013-02-0100008161532012-02-022013-02-010000816153tit4:S000011844Member2012-02-022013-02-010000816153tit4:S000025152Member2012-02-022013-02-010000816153tit4:S000011843Member2012-02-022013-02-010000816153tit4:S000011841Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:C000001427Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:C000001438Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:C000001449Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:C000032344Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:C000032345Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:C000032346Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:C000032354Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:C000032355Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:C000032356Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:C000032352Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:C000032353Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:C000042667Member2012-02-022013-02-010000816153tit4:S000000540Memberrr:AfterTaxesOnDistributionsMembertit4:C000001427Member2012-02-022013-02-010000816153tit4:S000000540Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000001427Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000001427Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000001438Member2012-02-022013-02-010000816153tit4:S000000540Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000001449Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:C000075018Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:C000075019Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:C000075020Member2012-02-022013-02-010000816153tit4:S000011844Memberrr:AfterTaxesOnDistributionsMembertit4:C000032354Member2012-02-022013-02-010000816153tit4:S000011844Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032354Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032354Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032355Member2012-02-022013-02-010000816153tit4:S000011844Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032356Member2012-02-022013-02-010000816153tit4:S000011841Memberrr:AfterTaxesOnDistributionsMembertit4:C000032344Member2012-02-022013-02-010000816153tit4:S000011841Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032344Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000032344Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000032345Member2012-02-022013-02-010000816153tit4:S000011841Membertit4:BofaMerrillLynchOneTenYearIndexMembertit4:C000032346Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000042667Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032353Member2012-02-022013-02-010000816153tit4:S000011843Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032352Member2012-02-022013-02-010000816153tit4:S000011843Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032352Member2012-02-022013-02-010000816153tit4:S000011843Memberrr:AfterTaxesOnDistributionsMembertit4:C000032352Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:BofaMerrillLynchMasterIndexMembertit4:C000075020Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:BofaMerrillLynchMasterIndexMembertit4:C000075019Member2012-02-022013-02-010000816153tit4:S000025152Membertit4:BofaMerrillLynchMasterIndexMembertit4:C000075018Member2012-02-022013-02-010000816153tit4:S000025152Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000075018Member2012-02-022013-02-010000816153tit4:S000025152Memberrr:AfterTaxesOnDistributionsMembertit4:C000075018Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:C000032361Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:C000032362Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:C000032363Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:C000032364Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMember2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:C000032357Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:C000032358Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:C000032359Member2012-02-022013-02-010000816153tit4:S000011848Membertit4:C000032368Member2012-02-022013-02-010000816153tit4:S000011848Membertit4:C000083544Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:C000032347Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032361Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032361Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:SandpFiveHundredIndexMembertit4:C000032361Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:SandpFiveHundredIndexMembertit4:C000032362Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:SandpFiveHundredIndexMembertit4:C000032363Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMembertit4:SandpFiveHundredIndexMembertit4:C000032364Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032357Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032357Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:BarclaysIntermediateGovtCreditIndexMembertit4:C000032357Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:BarclaysIntermediateGovtCreditIndexMembertit4:C000032358Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMembertit4:BarclaysIntermediateGovtCreditIndexMembertit4:C000032359Member2012-02-022013-02-010000816153tit4:S000011848Memberrr:AfterTaxesOnDistributionsMembertit4:C000032368Member2012-02-022013-02-010000816153tit4:S000011848Memberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032368Member2012-02-022013-02-010000816153tit4:S000011848Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000032368Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:AbciMember2012-02-022013-02-010000816153tit4:S000011848Membertit4:BofaMerrillLynchThreeFifteenYearIndexMembertit4:C000083544Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000011848Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:C000032348Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:C000032349Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:C000032350Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000032350Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000032349Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000032348Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000032347Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032347Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:AbciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032347Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:C000032369Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:C000032370Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:C000032371Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:C000032372Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:C000056390Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:C000056391Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032369Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032369Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:EafeIndexMembertit4:C000032369Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:EafeIndexMembertit4:C000032370Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:EafeIndexMembertit4:C000032371Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMembertit4:EafeIndexMembertit4:C000032372Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BarclaysUsUniversalIndexMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BlendedBenchmarkMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BarclaysUsUniversalIndexMembertit4:C000056390Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BlendedBenchmarkMembertit4:C000056390Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BarclaysUsUniversalIndexMembertit4:C000056391Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:AciMembertit4:BlendedBenchmarkMembertit4:C000056391Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:AbciMember2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:C000032375Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:C000032376Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:C000032377Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032375Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032375Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000032375Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000032376Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:AciMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000032377Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:C000032380Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:C000032381Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:C000032382Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:C000042665Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:C000042664Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:C000042663Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:C000042672Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:C000042671Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:C000032374Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:C000113849Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMembertit4:C000113848Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMembertit4:C000042668Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000032380Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000032380Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:SandpFiveHundredIndexMembertit4:C000032380Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:BlendedIndexMembertit4:C000032380Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:SandpFiveHundredIndexMembertit4:C000032381Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:BlendedIndexMembertit4:C000032381Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:SandpFiveHundredIndexMembertit4:C000032382Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMembertit4:BlendedIndexMembertit4:C000032382Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMember2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:C000081859Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:C000081860Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:C000081861Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMember2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMemberrr:AfterTaxesOnDistributionsMembertit4:C000042672Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042672Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:EafeIndexMembertit4:C000042672Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:EafeIndexMembertit4:C000042671Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:EafeIndexMembertit4:C000032374Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMembertit4:EafeIndexMembertit4:C000113849Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:C000034775Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:C000034776Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:C000034777Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000042668Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042668Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMembertit4:BarclaysIntermediateGovtCreditIndexMembertit4:C000042668Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000042664Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042664Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:MsciAcExUsGrowthIndexMembertit4:C000042664Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:MsciAcExUsGrowthIndexMembertit4:C000042665Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMembertit4:MsciAcExUsGrowthIndexMembertit4:C000042663Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMembertit4:BarclaysIntermediateGovtCreditIndexMembertit4:C000113848Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000081859Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000081859Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:MsciEmergingMarketsIndexMembertit4:C000081859Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:MsciEmergingMarketsIndexMembertit4:C000081860Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:AciMembertit4:MsciEmergingMarketsIndexMembertit4:C000081861Member2012-02-022013-02-010000816153tit4:S000011849Membertit4:RthreeRfourRfiveRsixMember2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:C000042670Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:C000042669Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:C000032366Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMemberrr:AfterTaxesOnDistributionsMembertit4:C000034775Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000034775Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:MsciAcWorldIndexsMembertit4:C000034775Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:MsciAcWorldIndexsMembertit4:C000034776Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:AciMembertit4:MsciAcWorldIndexsMembertit4:C000034777Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:AciMember2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000042670Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000042670Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042670Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000042669Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000032366Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMembertit4:C000042666Member2012-02-022013-02-010000816153tit4:S000011846Membertit4:RthreeRfourRfiveMember2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMembertit4:C000113847Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000042666Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042666Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000042666Member2012-02-022013-02-010000816153tit4:S000011842Membertit4:RthreeRfiveMembertit4:BarclaysIntermediateGovernmentBondIndexMembertit4:C000113847Member2012-02-022013-02-010000816153tit4:S000011845Membertit4:RthreeRfiveMember2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMembertit4:C000113850Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMembertit4:C000113851Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:C000042674Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:C000042673Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:C000032379Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:C000058465Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:C000058466Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:C000058467Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:C000123223Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMemberrr:AfterTaxesOnDistributionsMembertit4:C000058465Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000058465Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:MsciAcExUsGrowthIndexMembertit4:C000058465Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:MsciAcExUsGrowthIndexMembertit4:C000058466Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:MsciAcExUsGrowthIndexMembertit4:C000058467Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMembertit4:MsciAcExUsGrowthIndexMembertit4:C000123223Member2012-02-022013-02-010000816153tit4:S000015648Membertit4:RthreeRfourRfiveRsixMember2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000042674Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042674Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000042674Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000042673Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000056389Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMembertit4:BarclaysUsUniversalIndexMember2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMembertit4:RussellThirtyHundredGrowthIndexMembertit4:C000032379Member2012-02-022013-02-010000816153tit4:S000020097Membertit4:RthreeRfiveMembertit4:BlendedBenchmarkMember2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMember2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMember2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:C000058462Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:C000058463Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:C000058464Member2012-02-022013-02-010000816153tit4:S000011850Membertit4:RthreeRfourRfiveMember2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000058462Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:MsciAcWorldIndexsMembertit4:C000058462Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:MsciAcWorldIndexsMembertit4:C000058463Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMembertit4:MsciAcWorldIndexsMembertit4:C000058464Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMembertit4:C000081861Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000058462Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:C000042675Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:C000058461Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:C000047041Member2012-02-022013-02-010000816153tit4:S000012859Membertit4:RthreeRfourRfiveMember2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMembertit4:C000123224Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMembertit4:C000123225Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000042675Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000042675Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000042675Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:BlendedIndexMembertit4:C000042675Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000058461Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:BlendedIndexMembertit4:C000058461Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:SandpFiveHundredIndexMembertit4:C000047041Member2012-02-022013-02-010000816153tit4:S000011851Membertit4:RthreeRfourRfiveMembertit4:BlendedIndexMembertit4:C000047041Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsMembertit4:C000081861Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMemberrr:AfterTaxesOnDistributionsAndSalesMembertit4:C000081861Member2012-02-022013-02-010000816153tit4:S000027135Membertit4:RthreeRfiveMembertit4:MsciEmergingMarketsIndexMember2012-02-022013-02-01pureiso4217:USD<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgLimitedTermMunicipalFund column period compact * ~</div>2013-02-01485BPOS2012-09-30THORNBURG INVESTMENT TRUST0000816153false2013-01-292013-02-01<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgStrategicMunicipalIncomeFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgStrategicMunicipalIncomeFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgStrategicMunicipalIncomeFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgStrategicMunicipalIncomeFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgStrategicMunicipalIncomeFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgNewMexicoIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgNewMexicoIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgNewMexicoIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgNewMexicoIntermediateMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgCaliforniaLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgCaliforniaLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgCaliforniaLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgCaliforniaLimitedTermMunicipalFund column period compact * ~</div><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgCaliforniaLimitedTermMunicipalFund column period compact * ~</div><b>Investmen<a name="prob442321_3"></a>t Goal </b><b>Fees and <a name="prob442321_4"></a>Expenses of the Fund </b><b>Fund Summary Limited Term National Fund</b>The primary investment goal of Limited Term National Fund is to obtain as high a level of current income exempt from federal individual income tax as is consistent, in the view of the Fund&#8217;s investment advisor, with preservation of capital.The secondary goal of the Fund is to reduce expected changes in its share price compared to longer intermediate and long-term bond portfolios.0.0150000.00280.00280.00280.00250.00500.00190.00210.00110.00720.00990.0039<b>Invest<a name="prob442321_30"></a>ment Goal </b><b>Fees and <a name="prob442321_31"></a>Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.00.005<b>Example. </b><b>Portfolio Turnover. </b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 13.06% of the average value of its portfolio.<b>Principal I<a name="prob442321_33"></a>nvestment Risks </b><b>Past Perfor<a name="prob442321_34"></a>mance of the Fund </b>The following information provides some indication of the risks of investing in Limited Term California Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 1-10 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares </b>222151400.015003773150.0051250.0050.0055450.00255470.005219010310.00212134930.00220.00120.00950.01220.0062After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.10131554712130.0200000.006<b>Investme<a name="prob442321_39"></a>nt Goal </b><b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b><b>Fees and Ex<a name="prob442321_40"></a>penses of the Fund </b>You would pay the following expenses if you did not redeem your Class C shares:This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:24517463You would pay the following expenses if you did not redeem your Class C shares:<b>Portfolio Turnover.</b>0.00480.00480.0048The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 12.72% of the average value of its portfolio.<b>Principal Invest<a name="prob442321_5"></a>ment Strategies </b>0.00250.00604483871990.0020.00230.0013<b>Example.</b>0.00930.01310.00610.00930.01240.0061The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by states and state agencies, local governments and their agencies and by certain United States territories and possessions. Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated at the time of purchase as investment grade or, if unrated, are issued by obligors which have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund&#8217;s portfolio is &#8220;laddered&#8221; by investing in obligations of different maturities so that some obligations mature during each of the coming years. <br /><br /> Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity normally less than five years. During temporary periods the Fund&#8217;s portfolio maturity may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.<br/><br/>The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.<br/><br/>The Fund normally invests 100% of its assets in municipal obligations. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax.<b>Principal Inv<a name="prob442321_6"></a>estment Risks </b><b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 11.66% of the average value of its portfolio.<b>Princip<a name="prob442321_41"></a>al Investment Strategies </b>66867034612991477774An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Interest Rate Risk </b>&#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations and for any investments by the Fund in lower-rated or unrated municipal obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Credit Risk </b> &#8211; If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br /><br /> <b>Market and Economic Risk </b>&#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br /><br /> <b>Liquidity Risk </b>&#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price. <br /><br /> Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.The following information provides some indication of the risks of investing in Limited Term National Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 1-10 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.-0.0007<b>Annual Total Returns &#8211; Class A Shares </b>0.020000Highest quarterly results for time period shown: 4.49% <br/>(quarter ended 9-30-09).<br/><br/>Lowest quarterly results for time period shown: -1.66% <br/>(quarter ended 12-31-10).The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.29318662490408195704711340<b>Average Annual Total Returns</b> (periods ended <br/>12-31-12)132015730.0057620.0050.00500.00250.00500.0020.00180.0011After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.0.01530.01520.01690.02980.04160.04170.03980.04890.03390.03390.03320.0424<b>Principal Inve<a name="prob442321_42"></a>stment Risks </b><b>Past Pe<a name="prob442321_43"></a>rformance of the Fund </b>The following information provides some indication of the risks of investing in Intermediate New Mexico Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class D and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.0.02290.02980.0420.0489<b>Annual Total Returns &#8211; Class A Shares </b>0.03260.04240.03410.02980.04830.020.0489000.03890.0424012640800.00671115730.00950.01180.00610.04070.03230.02340.03690.0292-0.04070.1370.02530.09490.05990.00750.00750.00750.00250.00600.00310.00430.0020.01310.01780.03880.00950.03870.03470.04880.04990.04880.06340.04880.01250.01550.00950.04920.04930.06180.04740.05050.06180.05690.06180.04080.04080.04020.05140.040.05140.04630.0514This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgIntermediateMunicipalFundBarChart column period compact * ~</div>
-0.0006-0.0023After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class D and Class I shares because the returns of the classes are different.325218971246015383033878989435266701742207611661477295120624973751950.01860.01880.01940.02980.02650.02980.03780.02980.04150.04140.03960.04890.04180.04890.04810.0489<b>Fund Summary</b> <b>Intermediate National Fund</b>0.03240.03230.03180.04240.03120.04240.03730.0424158538943<b>Investment<a name="prob442321_12"></a> Goal </b>2076715649340The primary investment goal of Intermediate National Fund is to obtain as high a level of current income exempt from federal individual income tax as is consistent, in the view of the Fund&#8217;s investment advisor, with preservation of capital.13431432762<b>Fund Summary Intermediate New Mexico Fund</b<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same.Although your actual costs may be higher or lower, based on these assumptions your costs would be:The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by the State of New Mexico and its agencies, and by New Mexico local governments and their agencies. Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated at the time of purchase as investment grade or, if unrated, are issued by obligors which have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by certain United States territories and possessions. The Fund&#8217;s portfolio is &#8220;laddered&#8221; by investing in obligations of different maturities so that some obligations mature during each of the coming years. <br /><br />Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. During temporary periods the Fund&#8217;s portfolio maturity may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification. <br /><br />The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. The objective of preserving capital may prevent the Fund from obtaining the highest yields available. <br /><br />Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in New Mexico which are exempt from New Mexico and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in New Mexico or issued by United States territories or possessions. The Fund may invest up to 20% of its assets in taxable securities which produce income not exempt from federal or New Mexico income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of the Fund&#8217;s income would be subject to federal and New Mexico income taxes.Highest quarterly results for time period shown: 5.19% <br />(quarter ended 9-30-09). <br /><br />Lowest quarterly results for time period shown: -2.93%<br/>(quarter ended 12-31-10).0.03060.1240.12720.0976The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.<b>Average Annual Total Returns</b> (periods ended<br/>12-31-12)You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.500000.04880.0366The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.0.04880.03130.04880.0180.01250.0126A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.0.0405An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.0.0404You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.0.03940.06180.0420.0618500000.0481Accordingly, the loss of money is a risk of investing in the Fund.0.06180.11660.03580.0358<b>Fees and Ex<a name="prob442321_13"></a>penses of the Fund </b>0.03540.05140.03520.0514Accordingly, the loss of money is a risk of investing in the Fund.0.07260.1008An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.0.07260.08830.07260.0603The following information provides some indication of the risks of investing in Intermediate New Mexico Fund by showing how the Fund&#8217;s investment results vary from year to year.0.0757This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.0.0748<b>Example.</b>You would pay the following expenses if you did not redeem your Class C shares:The average annual total return figures compare Class A, Class D and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance.<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 16.94% of the average value of its portfolio.0.1080.10670.09860.0799<b>Principal Investmen<a name="prob442321_14"></a>t Strategies </b>0.11080.07990.1171Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.0.0799<b>Principal Inves<a name="prob442321_15"></a>tment Risks </b>www.thornburg.comThe following information provides some indication of the risks of investing in Intermediate National Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.1-800-847-0200<b>Annual Total Returns &#8211; Class A Shares </b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.The primary investment goal of Limited Term California Fund is to obtain as high a level of current income exempt from federal and California state individual income taxes as is consistent, in the view of the Fund&#8217;s investment advisor, with preservation of capital.The secondary goal of the Fund is to reduce expected changes in its share price compared to longer intermediate and long-term bond portfolios.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class D and Class I shares because the returns of the classes are different.The following information provides some indication of the risks of investing in Limited Term National Fund by showing how the Fund&#8217;s investment results vary from year to year.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 1-10 Year U.S. Municipal Securities Index, a broad measure of market performance.<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations and for any investments by the Fund in lower-rated or unrated municipal obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Credit Risk &#8211;</b> If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br /><br /> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br /><br /> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price. <br /><br /> <b>Single State Risk &#8211;</b> Because the Fund invests primarily in obligations originating in New Mexico, the Fund&#8217;s share value may be more sensitive to adverse economic, political or regulatory developments in that state. The recent recession has had a significant impact on New Mexico&#8217;s economy. Budgetary concerns and decreased revenues may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.<br/><br/><b>Diversification Risk &#8211;</b> The Fund is a nondiversified investment company, which means that it may invest a greater proportion of its assets in the securities of a single issuer. This may be riskier, because a default or other adverse condition affecting such an issuer could cause the Fund&#8217;s share price to decline to a greater degree. <br/><br/>Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by states and state agencies, local governments and their agencies, and by certain United States territories and possessions. Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated at the time of purchase as investment grade or, if unrated, are issued by obligors which have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund&#8217;s portfolio is &#8220;laddered&#8221; by investing in obligations of different maturities so that some obligations mature during each of the coming years. <br/><br/>Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. During temporary periods the Fund&#8217;s portfolio maturity may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification. <br/><br/>The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. The objective of preserving capital may prevent the Fund from obtaining the highest yields available. <br/><br/> The Fund normally invests 100% of its assets in municipal obligations. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk &#8211; </b>The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations and for any investments by the Fund in lower-rated or unrated municipal obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk</b> &#8211; If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br/><br/><b>Market and Economic Risk</b> &#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br/><br/><b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price. <br/><br/>Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.www.thornburg.comHighest quarterly results for time period shown: 6.76% <br/> (quarter ended 9-30-09).<br/><br/> Lowest quarterly results for time period shown: -3.50%<br/>(quarter ended 12-31-10).Highest quarterly results<b>Average Annual Total Returns</b> (periods ended <br/>12-31-12)2009-09-301-800-847-02000.0519After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.Lowest quarterly resultsActual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.2010-12-31The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.-0.0293After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes.Highest quarterly results2009-09-300.0676Lowest quarterly results2010-12-31-0.035Highest quarterly results2009-09-301-800-847-02000.0449www.thornburg.comPast performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.Lowest quarterly results2010-12-31The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance.The following information provides some indication of the risks of investing in Intermediate National Fund by showing how the Fund&#8217;s investment results vary from year to year.-0.01660.03870.02940.01760.03430.03572009-04-012009-04-012009-04-012009-04-012009-04-01Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.0.1694A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.500002009-04-012009-04-012009-04-01<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgLimitedTermMunicipalFundBarChart column period compact * ~</div>
0.03250.01690.01250.03010.03910.010.08850.030.0670.0307February 1, 20140.00450.09330.01750.0780.0331<b>Past Performance of the Fund </b><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgNewMexicoIntermediateMunicipalFundBarChart column period compact * ~</div>
2007-02-012007-02-01<b>Princip<a name="prob442321_32"></a>al Investment Strategies </b>0.04500000.050.010<b>Inve<a name="prob442321_57"></a>stment Goal </b><b>Fees and <a name="prob442321_58"></a>Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.0.00760.00760.00760.00760.00250.010.0100.00310.00580.00330.00170.01320.02340.02090.0093<b>Fund Summary</b> <b>Strategic Municipal Income Fund</b><b>Investment Goal</b>The Fund seeks a high level of current income exempt from federal individual income tax.The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.<b>Fees an d Expenses of the Fund</b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:0.01500You would pay the following expenses if you did not redeem your Class C shares:<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 12.52% of the average value of its portfolio.<b>Principal Investment Strategies </b>Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s investments in pursuing the Fund&#8217;s investment goal. The Fund invests principally in a portfolio of municipal obligations issued by states and state agencies, local governments and their agencies, and by certain United States territories and possessions. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, the difference in yields between higher and lower-rated obligations, and analysis of specific obligations. The Fund invests in obligations and participations in obligations of any credit quality. The Fund may invest up to 50 percent of its portfolio in lower-quality debt obligations rated at the time of purchase as below investment grade (sometimes called &#8220;junk&#8221; bonds or &#8220;high yield&#8221; bonds) or, if unrated, issued by obligors with comparable below investment grade obligations outstanding or deemed by Thornburg to be comparable to obligors with outstanding below investment grade obligations. The Fund may also invest in obligations that are in default at the time of purchase. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants.<br/><br/>The Fund may invest in municipal obligations of any maturity, but seeks to maintain a portfolio of investments having a dollar-weighted average effective duration of normally one to ten years. Duration is a measure of a municipal obligation&#8217;s sensitivity to interest rate changes. A portfolio with a longer average effective duration will typically be more sensitive to interest rate changes than a portfolio with a shorter average effective duration. During temporary periods the Fund&#8217;s average effective duration and average portfolio maturity may be reduced for defensive purposes. There is no limitation on the duration or maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund attempts to reduce changes in its share value through credit analysis, selection and diversification.<br/><br/>The Fund normally invests 100% of its assets in municipal obligations. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal income tax. Gains realized on investments held by the Fund and not offset by realized losses will be subject to federal income tax.<br/><br/>The Fund also may invest in derivative instruments such as options, futures contracts, options on futures contracts, and swap agreements (including, but not limited to, credit default swap agreements), to the extent Thornburg believes such investments may assist the Fund in pursuing its investment goal.<b>Principal Investment Risks </b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund&#8217;s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.<br/><br/><b>Management Risk</b> &#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk</b> &#8211; If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br/><br/><b>High Yield Risk</b> &#8211; Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer&#8217;s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.<br/><br/><b>Market and Economic Risk</b> &#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br/><br/><b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.<br/><br/><b>Derivatives Risk</b> &#8211; The Fund&#8217;s investments in derivatives involve the risks associated with the securities or other assets underlying the derivatives, and also may involve risks different or greater than the risks affecting the underlying assets, including the inability or unwillingness of the other party to a derivative to perform its obligations to the Fund, the Fund&#8217;s inability or delays in selling or closing positions in derivatives, and difficulties in valuing derivatives.<br/><br/> Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in Strategic Municipal Income Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch Municipal Master Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.0.0254<b>Annual Total Returns &#8211; Class A Shares</b>0.0143The primary investment goal of Intermediate New Mexico Fund is to obtain as high a level of current income exempt from federal and New Mexico state individual income taxes as is consistent, in the view of the Fund&#8217;s investment advisor, with preservation of capital.The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.0.01Highest quarterly results for time period shown: 11.53%<br/>(quarter ended 9-30-09).<br/><br/>Lowest quarterly results for time period shown: -5.38%<br/>(quarter ended 12-31-10).00.00500.03210.03510.00580.08450.03260.06740.0344<b>Fund Summary Government Fund</b>The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Average Annual Total Returns</b> (periods ended <br/>12-31-12)The primary goal of Government Fund is to provide as high a level of current income as is consistent, in the view of the Fund&#8217;s investment advisor, with safety of capital.After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.<b>Past Performanc e of the Fund </b>As a secondary goal, the Fund seeks to reduce changes in its share price compared to longer term portfolios.<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:<b>Example.</b>You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.50000An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /><b>Management Risk </b>&#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations and for any investments by the Fund in lower-rated or unrated municipal obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /><b>Credit Risk </b>&#8211; If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br /><br /><b>Market and Economic Risk </b>&#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br /><br /><b>Liquidity Risk </b>&#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.<br /><br /><b>Single State Risk </b>&#8211; Because the Fund invests primarily in obligations originating in California, the Fund&#8217;s share value may be more sensitive to adverse economic, political or regulatory developments in that state. The recent recession has had a significant impact on California&#8217;s economy. Budgetary concerns and decreased revenues may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.<br /><br />Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.Highest quarterly results for time period shown: 4.55% <br/> (quarter ended 9-30-09).<br/><br/> Lowest quarterly results for time period shown: -1.90%<br/>(quarter ended 12-31-10).<b>Average Annual Total Returns </b>(periods ended<br/>12-31-12)February 1, 20140.1252An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.0.00420.0042Accordingly, the loss of money is a risk of investing in the Fund.0.0042578737312950.00250.00584901080655296The following information provides some indication of the risks of investing in Strategic Municipal Income Fund by showing how the Fund&#8217;s investment results vary from year to year.This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:0.0026The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch Municipal Master Index, a broad measure of market performance.0.0026Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.0.0016114114501124www.thornburg.com5151-800-847-02000.00930.011819690.005824211143After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.2418Highest quarterly results2009-09-300.1153Lowest quarterly results-0.05382010-12-31<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 9.89% of the average value of its portfolio.<b>Princ<a name="prob442321_59"></a>ipal Investment Strategies </b>59243170237212730655442375186125011246576493242421<b>Principal <a name="prob442321_60"></a>Investment Risks</b>24181276143272637512064914320.020000.0050.0050.00250<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgStrategicMunicipalIncomeFundBarChart column period compact * ~</div>
0.0030.00270.01050.0077-0.0006-0.0010.00990.0067<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in Government Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Barclays Capital Intermediate Government Bond Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares </b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.500000.04770.0608You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.0.0989Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.The following information provides some indication of the risks of investing in Government Fund by showing how the Fund&#8217;s investment results vary from year to year.You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.The average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Barclays Capital Intermediate Government Bond Index, a broad measure of market performance.50000Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg.comA 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.1-800-847-02000.04370.13060.0245The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.0.34990.01280.07210.0952An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.0.2197Accordingly, the loss of money is a risk of investing in the Fund.0.0614The following information provides some indication of the risks of investing in Limited Term California Fund by showing how the Fund&#8217;s investment results vary from year to year.-0.41560.0355The average annual total return figures compare Class A, Class C and Class I share performance to the Bank of America Merrill Lynch 1-10 Year U.S. Municipal Securities Index, a broad measure of market performance.0.45260.0602Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.-0.03550.0915www.thornburg.com0.1655-0.13441-800-847-02000.06260.10650.0508After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.0.075The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.Highest quarterly resultsLowest quarterly results2008-12-310.05670.03490.05670.03690.160.0455Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.0.162004-06-300.08810.160.11140.16-0.02440.0590.04690.03840.0389-0.03260.0667-0.03440.0389<b>Average Annual Total Returns </b> (periods ended <br/>12-31-12)-0.02850.07870.01660.0389-0.03620.0166-0.0310.0166-0.01990.0166Highest quarterly results for time period shown: 3.49%<br/>(quarter ended 12-31-08).<br/><br/>Lowest quarterly results for time period shown: -2.44%<br/>(quarter ended 6-30-04).<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgCaliforniaLimitedTermMunicipalFundBarChart column period compact * ~</div>
Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio in pursuing the Fund&#8217;s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund&#8217;s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security before its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to market conditions.<br/><br/>Government Fund invests at least 80% of its assets in U.S. Government Securities. For this purpose, &#8220;U.S. Government Securities&#8221; means:<p style="PADDING-LEFT: 15px">Securities backed by the full faith and credit of the U.S. government, including direct obligations of the U.S. Treasury (such as U.S. Treasury Bonds) and obligations of U.S. government agencies and instrumentalities which are guaranteed by the U.S. Treasury (such as &#8220;Ginnie Mae&#8221; mortgage-backed certificates issued by the Government National Mortgage Association).</p><p style="PADDING-LEFT: 15px">Securities issued or guaranteed by U.S. government agencies, instrumentalities or sponsored enterprises, but which are not backed by the full faith and credit of the U.S. government. These securities include mortgage-backed certificates, collateralized mortgage obligations (&#8220;CMOs&#8221;), and debentures issued by &#8220;Freddie Mac&#8221; (Federal Home Loan Mortgage Corporation) and &#8220;Fannie Mae&#8221; (Federal National Mortgage Association).</p>U.S. Government Securities include for this purpose repurchase agreements secured by the securities described above, and participations having economic characteristics similar to those securities. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants.<br/><br/>Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.0.05690.0524Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund&#8217;s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund&#8217;s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value and dividends may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund&#8217;s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br/><br/><b>Prepayment Risk &#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk &#8211;</b> All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund&#8217;s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government-sponsored enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund are rated &#8220;Aaa&#8221; by Moody&#8217;s Investors Services or &#8220;AA+&#8221; by Standard and Poor&#8217;s Corporation. Ratings agencies may reduce the ratings of any securities in the future.<br/><br/><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.<br/><br/><b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices.<br/><br/>Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.0.04840.0710.05480.0710.05370.0710.06590.0710.05860.04350.04130.05180.0590.05180.06540.05180.04690.03240.03150.04620.04570.04620.05190.046200.00502996852223676241814529450.0280.02820.02780.0488<b>Investment <a name="prob442321_84"></a>Goal </b>0.04710.04710.04510.06180.03750.03750.03690.05140.02380.01210.01070.03330.06760.06780.03920.03590.03730.02010.05250.04880.05990.06062010-02-012010-02-01<b>Fund Summary Income Fund</b><b>Invest<a name="prob442321_66"></a>ment Goal </b><br /><br />The primary goal of Income Fund is to provide as high a level of current income as is consistent, in the view of the Fund&#8217;s investment advisor, with safety of capital.As a secondary goal, the Fund seeks to reduce changes in its share prices compared to longer term portfolios.<b>Fees and Ex<a name="prob442321_67"></a>penses of the Fund </b>0.03210.0230.01680.03440.03370.0078Highest quarterly results0.08712009-09-300.01860.04550.0970.0492Lowest quarterly results2010-12-31-0.019<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:You would pay the following expenses if you did not redeem your Class C shares:This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 23.72% of the average value of its portfolio.<b>Princi<a name="prob442321_68"></a>pal Investment Strategies</b><b>Example.</b><b>Portfolio Turnover.</b><b>Princip<a name="prob442321_50"></a>al Investment Strategies </b><b>Principal <a name="prob442321_51"></a>Investment Risks </b>Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio in pursuing the Fund&#8217;s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund&#8217;s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions.<br/><br/>The Fund invests at least 65% of its net assets in (i) obligations of the U.S. government, its agencies and instrumentalities, and (ii) debt obligations rated at the time of purchase in one of the three highest ratings of Standard &amp; Poor&#8217;s Corporation (AAA, AA or A) or Moody&#8217;s Investors Services, Inc. (Aaa, Aa or A) or, if no credit rating is available, judged to be of comparable quality by Thornburg. The Fund will not invest in any debt obligation rated at the time of purchase lower than BBB by Standard &amp; Poor&#8217;s or Baa by Moody&#8217;s or of equivalent quality as determined by Thornburg. The Fund may purchase debt obligations such as corporate debt obligations, mortgage-backed securities, other asset-backed securities, municipal securities, and commercial paper and bankers&#8217; acceptances. The Fund may purchase foreign securities of the same types and quality as the domestic securities it purchases when Thornburg anticipates foreign securities offer more investment potential.<br/><br/>Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.<b>Past Perform<a name="prob442321_52"></a>ance of the Fund</b><b>Principal Inve<a name="prob442321_69"></a>stment Risks </b>The following information provides some indication of the risks of investing in Intermediate New York Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares</b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class I shares because the returns of the classes are different.The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.The secondary, non-fundamental goal of the Fund is to seek some current income.<b>Fees and Ex<a name="prob442321_85"></a>penses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions, your costs would be:You would pay the following expenses if you did not redeem your Class B or C shares:<b>Fund Summary Limited Term California Fund</b><b>Pas<a name="prob442321_70"></a>t Performance of the Fund </b>The following information provides some indication of the risks of investing in Income Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Barclays Capital Intermediate Government/Credit Bond Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 54.16% of the average value of its portfolio.<b>Annual Total Returns &#8211; Class A Shares </b>The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by the State of California and its agencies, and by California local governments and their agencies. Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated at the time of purchase as investment grade or, if unrated, are issued by obligors which have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by certain United States territories and possessions. The Fund&#8217;s portfolio is &#8220;laddered&#8221; by investing in obligations of different maturities so that some obligations mature during each of the coming years.<br /><br />Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity normally less than five years. During temporary periods the Fund&#8217;s portfolio maturity may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.<br /><br />The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.<br /><br />Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in California which are exempt from California and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in California or issued by United States territories and possessions. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal or California income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of its income would be subject to federal and California income taxes.<b>Average Annual Total Returns </b>(periods ended<br/>12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund&#8217;s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund&#8217;s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk</b> &#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value and dividends may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund&#8217;s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br/><br/><b>Prepayment Risk</b> &#8211; Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk</b> &#8211; All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund&#8217;s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government sponsored enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund, are rated &#8220;Aaa&#8221; by Moody&#8217;s Investors Services or &#8220;AA+&#8221; by Standard and Poor&#8217;s Corporation. Ratings agencies may reduce the ratings of any securities in the future. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades.<br/><br/><b>Market and Economic Risk</b> &#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.<br/><br/><b>Foreign Investment Risk</b> &#8211; Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.<br/><br/><b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices.<br/><br/>Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.0.237250000An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgValueFund column period compact * ~</div>
Accordingly, the loss of money is a risk of investing in the Fund.The following information provides some indication of the risks of investing in Income Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class C and Class I share performance to the Barclays Capital Intermediate Government/Credit Bond Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg.com1-800-847-0200Highest quarterly results for time period shown: 6.76%<br/>(quarter ended 6-30-09).<br/><br/>Lowest quarterly results for time period shown: -2.65%<br/>(quarter ended 9-30-08).The sales charge for Class A shares is not reflected in the returns shown in the bar chart above and the returns would be less if the charge was taken into account.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgValueFund column period compact * ~</div>
Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.<b>Invest<a name="prob442321_75"></a>ment Goal </b><b>Fund Summary Strategic Income Fund</b><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgValueFund column period compact * ~</div>
Highest quarterly resultsThe Fund&#8217;s primary investment goal is to seek a high level of current income.2009-06-30The Fund&#8217;s secondary investment goal is some long-term capital appreciation.0.0676<b>Fee<a name="prob442321_76"></a>s and Expenses of the Fund </b>Lowest quarterly resultsThis table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.2008-09-30-0.0265<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgValueFund column period compact * ~</div>
<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be: <br /><br /><div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgValueFundBarChart column period compact * ~</div>
You would pay the following expenses if you did not redeem your Class C shares:<b>Fund Summary</b> <b>Intermediate New York Fund</b><b>Investment Goal </b>0.015000The primary investment goal of Intermediate New York Fund is to obtain as high a level of current income exempt from federal, New York State and New York City individual income taxes as is consistent, in the view of the Fund&#8217;s investment advisor, with preservation of capital.The secondary goal of the Fund is to reduce expected changes in its share price compared to long-term bond portfolios.<b>Fees and Expenses of the Fund </b><b>Shareholder Fees </b><br />(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br />(expenses that you pay each year as a percentage of the value of your investment)<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgValueFund column period compact * ~</div>
This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:<b>Average Annual Total Returns </b>(periods ended<br /> 12-31-12)The Fund pursues its primary goal by investing principally in a laddered maturity portfolio of municipal obligations issued by New York State and its agencies, and by New York State local governments and their agencies. Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio. Investment decisions are based upon outlooks for interest rates and securities markets, the supply of municipal debt obligations, and analysis of specific securities. The Fund invests in obligations and participations in obligations which are rated at the time of purchase as investment grade or, if unrated, are issued by obligors which have comparable investment grade obligations outstanding or which are deemed by Thornburg to be comparable to obligors with outstanding investment grade obligations. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants. The Fund may invest in obligations issued by certain United States territories and possessions. The Fund&#8217;s portfolio is &#8220;laddered&#8221; by investing in obligations of different maturities so that some obligations mature during each of the coming years.<br /><br />Because the magnitude of changes in value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity of normally three to ten years. During temporary periods the Fund&#8217;s portfolio maturity may be reduced for defensive purposes. There is no limitation on the maturity of any specific security the Fund may purchase. The Fund may dispose of any security before it matures. The Fund also attempts to reduce changes in its share value through credit analysis, selection and diversification.<br /><br />The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. The objective of preserving capital may prevent the Fund from obtaining the highest yields available.<br /><br />Under normal conditions the Fund invests at least 80% of its assets in municipal obligations originating in New York State which are exempt from New York State and regular federal income taxes, and normally invests 100% of its assets in municipal obligations originating in New York or issued by United States territories and possessions. The Fund may invest up to 20% of its assets in taxable securities which would produce income not exempt from federal or New York income tax because of market conditions, pending investment of idle funds or to afford liquidity. The Fund&#8217;s temporary taxable investments may exceed 20% of its assets when made for defensive purposes during periods of abnormal market conditions. If the Fund found it necessary to own taxable investments, some of the Fund&#8217;s income would be subject to federal and New York State and City income taxes.00.050.0050An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk</b> &#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations and for any investments by the Fund in lower-rated or unrated municipal obligations. When interest rates decrease, the Fund&#8217;s dividends may decline. Decreases in market interest rates may also result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk</b> &#8211; If obligations held by the Fund are downgraded by ratings agencies or go into default, or if legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades. Municipal leases held by the Fund may be subject to non-appropriation provisions which permit governmental issuers to discontinue payments to the Fund under the leases.<br/><br/><b>Market and Economic Risk</b> &#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for the Fund&#8217;s investments in lower-rated and unrated municipal obligations, the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments, and developments affecting specific issuers.<br/><br/><b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. The market for lower-rated and unrated obligations may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.<br/><br/><b>Single State Risk</b> &#8211; Because the Fund invests primarily in obligations originating in New York, the Fund&#8217;s share value may be more sensitive to adverse economic, political or regulatory developments in that state. The recent recession has had a significant impact on New York&#8217;s economy. Budgetary concerns and decreased revenues may negatively affect the ability of state and local issuers to make full and timely principal or interest payments on their debt obligations.<br /><br /><b>Diversification Risk</b> &#8211; The Fund is a nondiversified investment company, which means that it may invest a greater proportion of its assets in the securities of a single issuer. This may be riskier, because a default or other adverse condition affecting such an issuer could cause the Fund&#8217;s share price to decline to a greater degree.<br /><br />Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.Highest quarterly results for time period shown: 5.26%<br />(quarter ended 9-30-09). <br /><br />Lowest quarterly results for time period shown: -2.88%<br />(quarter ended 12-31-10).You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.50000A 0.50% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.February 1, 20140.1337An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.Accordingly, the loss of money is a risk of investing in the Fund.<b>Diversification Risk</b> &#8211; The Fund is a nondiversified investment company, which means that it may invest a greater proportion of its assets in the securities of a single issuer. This may be riskier, because a default or other adverse condition affecting such an issuer could cause the Fund&#8217;s share price to decline to a greater degree.The following information provides some indication of the risks of investing in Intermediate New York Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A and Class I share performance to the Bank of America Merrill Lynch 3&#8211;15 Year U.S. Municipal Securities Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.1-800-847-0200www.thornburg.comThe sales charge for Class A shares is not reflected in the returns shown in the bar chart, and the returns would be less if the charge was taken into account.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class I shares because the returns of the classes are different.Highest quarterly results2009-09-300.0526Lowest quarterly results2010-12-31-0.0288<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgLimitedTermIncomeFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgLimitedTermIncomeFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgLimitedTermIncomeFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgLimitedTermIncomeFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgLimitedTermIncomeFundBarChart column period compact * ~</div>
0.00380.00380.00380.00380.00250.010.00500.00260.00870.00290.0017<b>Portfolio Turnover. </b>0.00890.02250.00550.0117<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgLimitedTermIncomeFund column period compact * ~</div>
<b>Principa<a name="prob442321_77"></a>l Investment Strategies </b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 34.54% of the average value of its portfolio.<b>Principal In<a name="prob442321_78"></a>vestment Risks </b>You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.239728169564301053372176636140564430712301420689<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgNewYorkIntermediateMunicipalFund column period compact * ~</div>
2238<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgNewYorkIntermediateMunicipalFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgNewYorkIntermediateMunicipalFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgNewYorkIntermediateMunicipalFundBarChart column period compact * ~</div>
22811970337212056441420<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgNewYorkIntermediateMunicipalFund column period compact * ~</div>
2238An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund&#8217;s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.<br /><br /><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /><b>Interest Rate Risk</b> <b>&#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br /><br /><b>Prepayment Risk</b> <b>&#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /><b>Credit Risk</b> <b>&#8211;</b> If obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. Debt obligations backed by so-called &#8220;subprime&#8221; mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk.<br /><br /><b>High Yield Risk</b> <b>&#8211;</b> Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer&#8217;s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.<br /><br /><b>Market and Economic Risk</b> <b>&#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for lower-rated and unrated debt obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments. The market value of any zero coupon bonds or &#8220;stripped&#8221; securities that the Fund may purchase will typically be more volatile than the value of a comparable, interest-paying bond. Additionally, zero coupon bonds and &#8220;stripped&#8221; securities are subject to the risk that the Fund may have to recognize income on its investment and make distributions to shareholders before it has received any cash payments on its investment.<br /><br /><b>Risks Affecting Specific Issuers</b> <b>&#8211;</b> The value of a debt obligation or equity security may decline in response to developments affecting the specific issuer of the obligation or security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /><b>Liquidity Risk </b><b>&#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. The market for lower-rated and unrated debt obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) and debt obligations backed by so-called &#8220;subprime&#8221; mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.<br /><br /><b>Smaller Company Risk</b> <b>&#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /><b>Foreign Investment Risk</b> <b>&#8211;</b> Investments in the equity securities or debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.<br /><br /><b>Structured Products Risk</b> <b>&#8211;</b> The Fund&#8217;s investments in structured finance arrangements, including CMOs, CDOs, CBOs and CLOs, involve the risks associated with the underlying pool of securities or other assets, and also may involve risks different or greater than the risks affecting the underlying assets. In particular, these investments may be less liquid than other debt obligations, making it difficult for the Fund to value its investment or sell the investment in a timely manner or at an acceptable price.<br /><br /><b>Derivatives Risk</b> <b>&#8211;</b> The Fund&#8217;s investments in derivatives involve the risks associated with the securities or other assets underlying the derivatives, and also may involve risks different or greater than the risks affecting the underlying assets, including the inability or unwillingness of the other party to a derivative to perform its obligations to the Fund, the Fund&#8217;s inability or delays in selling or closing positions in derivatives, and difficulties in valuing derivatives.<br /><br /><b>Real Estate Risk</b> <b>&#8211;</b> The Fund&#8217;s investments in real estate investment trusts (&#8220;REITs&#8221;) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT).<br /><br />Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.<b>Past Perf<a name="prob442321_79"></a>ormance of the Fund </b>0.01730.02350.01310.01730.01730.0173-0.04360.0049-0.00420.0031The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total return for Class A shares has been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I performance to the Barclays Capital U.S. Universal Index, a broad measure of market performance, and to a Blended Benchmark, comprised of 80% Barclays Capital Aggregate Bond Index, which represents a broad measure of bond market performance, and 20% MSCI World Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.0.03680.0260.02520.04510.0233<b>Annual Total Returns &#8211; Class A Shares </b>0.04510.04510.03710.04320.04510.0410.03770.0410.03160.0410.02430.03310.02230.02190.041The Fund pursues its investment goals by investing in a broad range of income-producing investments from throughout the world, primarily including debt obligations and income-producing stocks. The Fund expects, under normal conditions, to invest a majority of its assets in the debt obligations described below, but the relative proportions of the Fund&#8217;s investments in debt obligations and in income producing stocks can be expected to vary over time.<br/><br/>The Fund may invest in debt obligations of any kind, of any quality, and of any maturity. The Fund expects, under normal conditions, to select a majority of its investments from among the following types of debt obligations:<ul type="square"><li>bonds and other debt obligations issued by domestic and foreign companies of any size (including lower-rated &#8220;high yield&#8221; or &#8220;junk&#8221; bonds) </li></ul><ul type="square"><li>mortgage-backed securities and other asset-backed securities</li></ul><ul type="square"><li>convertible debt obligations</li></ul><ul type="square"><li>obligations issued by foreign governments (including developing countries) </li></ul><ul type="square"><li>collateralized mortgage obligations (&#8220;CMOs&#8221;), collateralized debt obligations (&#8220;CDOs&#8221;), collateralized bond obligations (&#8220;CBOs&#8221;), collateralized loan obligations (&#8220;CLOs&#8221;), and other structured finance arrangements</li></ul><ul type="square"><li>obligations of the U.S. government and its agencies and sponsored enterprises</li></ul><ul type="square"><li>other derivative instruments and structured notes</li></ul><ul type="square"><li>zero coupon bonds and &#8220;stripped&#8221; securities</li></ul><ul type="square"><li>taxable municipal obligations and participations in municipal obligations</li></ul>The Fund may invest in any stock or other equity security which the investment advisor believes may assist the Fund in pursuing its investment goals, including primarily income producing common and preferred stocks issued by domestic and foreign companies of any size (including smaller companies with market capitalizations of less than $500 million, and companies in developing countries), and also including publicly traded real estate investment trusts and other equity trusts and partnership interests. The Fund expects that its equity investments will be weighted in favor of companies that pay dividends or other current income.<br/><br/>The Fund&#8217;s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such investment prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or otherwise to respond to market conditions.Highest quarterly results for time period shown: 16.23% <br/>(quarter ended 6-30-09).<br/><br/>Lowest quarterly results for time period shown: -10.38% <br/>(quarter ended 12-31-08).You would pay the following expenses if you did not redeem your Class B or C shares:0.04500000.050.010February 1, 20140.3454Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class C and Class I performance to the Barclays Capital U.S. Universal Index, a broad measure of market performance, and to a Blended Benchmark, comprised of 80% Barclays Capital Aggregate Bond Index, which represents a broad measure of bond market performance, and 20% MSCI World Index, which represents a broad measure of equity market performance in developed markets.1-800-847-0200www.thornburg.comPast performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.0.00680.00680.00680.0068After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.0.00250.01Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts not subject to federal income tax.0.010A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.0.00360.00410.00350.0020.01290.02090.02030.0088Highest quarterly results2009-06-300.1623Lowest quarterly results2008-12-31-0.1038575712306908411005637281112613241093488193623581084<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgLimitedTermU.S.GovernmentFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgLimitedTermU.S.GovernmentFund column period compact * ~</div>
2214<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgLimitedTermU.S.GovernmentFund column period compact * ~</div>
212206<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgLimitedTermU.S.GovernmentFund column period compact * ~</div>
6556371124109323580.0450<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgLimitedTermU.S.GovernmentFundBarChart column period compact * ~</div>
02214<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgLimitedTermU.S.GovernmentFund column period compact * ~</div>
00.0100.10160.09730.06570.1732-0.0366-0.04-0.0327-0.03690.09950.09380.08620.08210.09450.1732-0.0392-0.03690.09750.0821-0.0006-0.00250.13550.1732-0.0347-0.03690.09650.08210.15850.1732-0.0238-0.03690.10930.0821<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgStrategicIncomeFund column period compact * ~</div>
0.00750.00750.00750.00250.0100.00310.0030.00210.00020.00020.0002<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgStrategicIncomeFund column period compact * ~</div>
0.01330.02070.00980.01270.01820.0098<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgStrategicIncomeFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgStrategicIncomeFund column period compact * ~</div>
<b>Investme<a name="prob442321_102"></a>nt Goal </b><b>Fees an<a name="prob442321_103"></a>d Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgStrategicIncomeFundBarChart column period compact * ~</div>
57428510084762531211411091542197423801201<b>Example.</b><b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 122.93% of the average value of its portfolio.185<b>Principa<a name="prob442321_104"></a>l Investment Strategies </b>62510912380<b>Principal Inv<a name="prob442321_105"></a>estment Risks </b>0.40020.17720.1770.25620.2771-0.41890.3143-0.18480.137-0.13240.3668<b>Past Per<a name="prob442321_106"></a>formance of the Fund </b>0.1533The following information provides some indication of the risks of investing in Growth Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Russell 3000 Growth Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.0.1310.04440.1255<b>Annual Total Returns &#8211; Class A Shares </b>0.07460.05060.04920.05540.0660.10870.05540.0660.12810.05540.0660.07190.04450.04520.06190.04850.07560.06190.04850.08470.06190.0485<b>Fees an<a name="prob442321_94"></a>d Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.0.07570.04840.04860.06230.04980.07940.06230.04980.08870.06230.0498<b>Example.</b><b>Portfolio Turnover. </b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 17.86% of the average value of its portfolio.<b>Pri<a name="prob442321_95"></a>ncipal Investment Strategies </b><b>Principal Inve<a name="prob442321_96"></a>stment Risks </b><b>Past Perfo<a name="prob442321_97"></a>rmance of the Fund </b>The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) Europe, Australasia and Far East (EAFE) Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares </b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.2007-12-192007-12-192007-12-192007-12-192007-12-192007-12-192007-12-192007-12-192007-12-192007-12-192007-12-190.04500000.010.00860.00860.00860.00250.0100.00380.00390.00220.01490.02250.01080.01490.02250.0099-0.000959510132890070333512271205587214925851309<b>Fund Summary</b> <b>International Value Fund</b>International Value Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.The secondary, non-fundamental goal of the Fund is to seek some current income.<b>Shareholder Fees </b><br />(fees paid directly from your investment)The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 13.37% of the average value of its portfolio.<b>Annual Fund Operating Expenses </b><br />(expenses that you pay each year as a percentage of the value of your investment)This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions your costs would be:<b>Average Annual Total Returns </b>(periods ended<br /> 12-31-12)An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk</b> &#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br/><br/><b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br/><br/><b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries.<br/><br/><b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments. <br/><br/><b>Credit Risk</b> &#8211; If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br /><br /><b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /><b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices.<br /><br />Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.Highest quarterly results for time period shown: 22.74%<br />(quarter ended 6-30-09). <br /><br />Lowest quarterly results for time period shown: -20.94%<br />(quarter ended 9-30-11).228703120525850.1786An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.Accordingly, the loss of money is a risk of investing in the Fund.The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) Europe, Australasia and Far East (EAFE) Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg.com1-800-847-0200After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.0.5645The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.0.15380.2209Highest quarterly results0.18110.22740.11422009-06-30-0.5095Lowest quarterly results0.4539-0.20940.09732011-09-300.01350.2142A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.500000.15980.15960.10370.15210.19510.15210.21950.1521You would pay the following expenses if you did not redeem your Class B or C shares:-0.0167-0.0166-0.01410.0315-0.01510.0315-0.0028<b>Average Annual Total Returns </b> (periods ended<br/>12-31-12)0.0315The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.0.1030.10280.09220.07690.09960.07690.07120.0578The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.2003-01-112003-01-11<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgStrategicIncomeFund column period compact * ~</div>
<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Fund Summary Growth Fund</b>You would pay the following expenses if you did not redeem your Class C shares:This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk</b> &#8211; The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Market and Economic Risk</b> &#8211; The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br /><br /> <b>Risks Affecting Specific Issuers</b> &#8211; The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /> <b>Smaller Company Risk</b> &#8211; Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /> <b>Foreign Investment Risk</b> &#8211; Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries.<br /><br /> <b>Credit Risk</b> &#8211; If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk. <br /><br/> <b>Interest Rate Risk</b> &#8211; When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Liquidity Risk</b> &#8211; Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. <br /><br /> Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.Highest quarterly results for time period shown: 31.27%<br/>(quarter ended 6-30-03). <br/><br/>Lowest quarterly results for time period shown:-26.95% <br/>(quarter ended 12-31-08).<b>Average Annual Total Returns</b> (periods ended<br/> 12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.February 1, 201450000You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds.A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.1.2293Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.The following information provides some indication of the risks of investing in Growth Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class C and Class I share performance to the Russell 3000 Growth Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg.com1-800-847-0200The sales charge for Class A shares is not reflected in the returns shown in the bar chart, and the returns would be less if the charge was taken into account.Highest quarterly results2003-06-300.3127Lowest quarterly results2008-12-31-0.2695The Fund invests primarily in foreign securities or depository receipts of foreign securities. The Fund may invest in developing countries, but under normal conditions those investments are expected to comprise a smaller proportion of the Fund than investments in developed countries. <br /><br />The Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;), intends to invest on an opportunistic basis where the Fund&#8217;s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks classified as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies. <br /><br /> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund&#8217;s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are: <table style="font-size: 10pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">profitability </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">undervalued assets</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/book value ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry growth characteristics</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">franchise value</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">dividend characteristics </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">potential for favorable developments</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">security and consistency of revenues </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">EBIT (earnings before interest and taxes)/interest<br/> expense ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">EV (enterprise value)/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table> <br />The Fund classifies its equity investments in the following three categories:<br /><br /> <b> Basic Value: </b>Companies which, in Thornburg&#8217;s opinion, are financially sound with well established businesses selling at low valuations relative to the companies&#8217; net assets or potential earning power.<br /><br /> <b> Consistent Earner: </b> Companies which normally exhibit steady earnings growth, cash flow characteristics and/or dividend growth. These companies may have above average profitability measures and normally sell at above average valuations.<br /><br /> <b>Emerging Franchise:</b> Companies which, in Thornburg&#8217;s opinion, are in the process of establishing a leading position in a product, service or market with the potential to grow at an above average rate. Under normal conditions, the proportion of the Fund invested in this category will be lower than the other categories.<br /><br />Debt obligations may be considered for investment if Thornburg believes them to be more attractive than equity alternatives, or to manage risk. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgInternationalValueFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgInternationalValueFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgInternationalValueFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgInternationalValueFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgInternationalValueFundBarChart column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgCoreGrowthFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgCoreGrowthFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgInternationalValueFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgCoreGrowthFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgCoreGrowthFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgCoreGrowthFundBarChart column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgCoreGrowthFund column period compact * ~</div>
You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.50000The Fund expects to invest primarily in domestic equity securities (primarily common stocks) selected for their growth potential. However, the Fund may own a variety of securities, including foreign equity securities and partnership interests. The Fund may invest in developing countries.<br /><br />The Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) intends to invest in companies that it believes will have growing revenues and earnings. The Fund can invest in companies of any size, from larger, well-established companies to smaller, emerging growth companies. <br /><br /> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are:<table style="font-size: pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">price/revenue ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">business model</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">PE/growth rate ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">industry growth potential</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">enterprise value/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">asset appreciation potential</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">management strength</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">potential size of business</td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">value based on earnings growth discount model</td> <td>&nbsp;</td> </tr><tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table><br/>The Fund typically makes equity investments in the following three types of companies: <br/><br/><b>Growth Industry Leaders</b> are growing companies that appear to have proprietary advantages in industry segments that Thornburg expects to grow faster than the overall market. Stocks of these companies generally sell at premium valuations (relative to the S&amp;P Composite 1500 Index).<br/><br/><b>Consistent Growth</b> companies. Stocks in this category generally sell at premium valuations (relative to the S&amp;P Composite 1500 Index) and tend to show steady earnings or cash flow growth, or both. There are no assurances that these trends will continue in the future.<br/><br/><b>Emerging Growth</b> companies are typically growing companies that in Thornburg&#8217;s opinion are in the process of establishing a leading position in a significant product, service or market and which Thornburg expects will grow, or continue to grow, at a rate exceeding the growth of the U.S. gross domestic product (&#8220;GDP&#8221;). These companies may not be profitable at the time of purchase.<br/><br/>In conjunction with individual issuer analysis, Thornburg may identify economic sectors it expects to experience growth. At times this approach may produce a focus on certain industries, such as technology, financial services, healthcare or biotechnology. The exposure to particular economic sectors or industries likely will vary over time. Investment decisions are also based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for debt and equity securities.<br/><br/>Debt obligations, usually with associated equity features, occasionally will be considered for investment when Thornburg believes them to be more attractive than equity alternatives. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.0.04500000.010.0070.0070.0070.00250.0100.00250.00270.00190.00230.00230.00230.01430.0220.01120.01430.02130.011200.045000.010000000000.00880.00680.00680.00685890.00683161140.0058820.0025681356000.00880.0088119611736170.00420.00520.00380.000820860.0025252813630.0100.0160.01450.01060.00760.00380.00390.0026<b>Fund Summary Developing World Fund</b><b>Investment Goal</b><b>Fees and Expenses of the Fund</b><b>Shareholder Fees</b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b><b>Portfolio Turnover.</b>0.01450.0125<b>Principal Investment Strategies</b>0.00990.0076Under normal market conditions the Fund invests at least 80% of its assets in equity securities and debt obligations of developing country issuers. A developing country issuer is a company or sovereign entity that is domiciled or otherwise tied economically to one or more developing countries. The Fund expects that investments in the Fund&#8217;s portfolio normally will be weighted in favor of equity securities. The Fund&#8217;s investment in debt obligations may include, but is not limited to, those of sovereign and corporate issuers. The Fund may purchase debt obligations of any maturity and credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics (such as convertible bonds). The Fund may invest in issuers of any size of capitalization, including small companies. <br/><br/>Currently, the Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) considers developing countries to include most Central and South American, African, Asian and Eastern European nations, including, but not limited to, Argentina, Austria, Brazil, Chile, China, Colombia, Czech Republic, Egypt, Hong Kong, Hungary, India, Indonesia, Israel, South Korea, Malaysia, Mexico, Morocco, Nigeria, Pakistan, Peru, Philippines, Poland, Qatar, Romania, the Russian Federation, Slovenia, South Africa, Taiwan, Thailand, Turkey, Ukraine, the United Arab Emirates and Vietnam. Thornburg identifies what it considers to be developing countries based upon its own analysis of measures of industrialization, economic growth, population growth and other factors, and may also consider classifications by the World Bank, the International Finance Corporation, the United Nations and independent financial services firms that maintain indices of developing countries. <br/><br/>Thornburg considers a variety of factors to determine whether an investment is tied economically to one or more developing countries, including (i) whether or not a significant portion of the issuer&#8217;s revenues or assets are derived from or are located in developing countries, (ii) the primary trading market of the issuer&#8217;s securities, (iii) the locations of its offices or other operations, (iv) the source of any governmental guarantees or other supports, (v) identification of the issuer&#8217;s securities within an index or other listing indicating its location in a particular developing country or region, and (vi) whether the investment is otherwise exposed to the economic fortunes and risks of developing countries. <br/><br/>The Fund&#8217;s policy of investing at least 80% of its assets in developing country issuers may be changed by the Fund&#8217;s Trustees without a shareholder vote upon 60 days&#8217; notice to shareholders. <br/><br/>Among the specific factors considered in identifying securities for inclusion in the Fund are domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. With respect to equity securities, the Fund typically makes investments in the following three types of issuers:<br/><br/><b>Basic Value:</b> Companies which, in Thornburg&#8217;s opinion, are financially sound with well established businesses selling at low valuations relative to the companies&#8217; net assets or potential earning power.<br/><br/><b>Consistent Earner:</b> Companies which normally exhibit steady earnings growth, cash flow characteristics and/or dividend growth. These companies may have above average profitability measures and normally sell at above average valuations.<br/><br/><b>Emerging Franchise:</b> Companies which, in Thornburg&#8217;s opinion, are in the process of establishing a leading position in a product, service or market with the potential to grow at an above average rate.<b>Principal Investment Risks</b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility. These risks may be more pronounced for the Fund&#8217;s investments in developing countries.<br/><br/><b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br/><br/><b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protections. These risks may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries.<br/><br/><b>Smaller Company Risk &#8211; </b>Investments in smaller companies may involve additional risks because of limited product lines,limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br/><br/><b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Some foreign government debt obligations may be subject to default, repudiation or renegotiation, delays in payment, or could be downgraded by ratings agencies. Additionally, because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br/><br/><b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund&#8217;s investments in developing countries.<br/><br/>Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.<b>Past Performance of the Fund</b>216<b>Annual Total Returns &#8211; Class A Shares </b>681Highest quarterly results for time period shown: 18.17%<br/>(quarter ended 9-30-10). <br/><br/>Lowest quarterly results for time period shown: -23.17%<br/>(quarter ended 9-30-11).<b>Average Annual Total Returns</b> (periods ended <br/> 12-31-12)1173After-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.2528000.01510.02270.0114000.01510.02270.0099The following information provides some indication of the risks of investing in Developing World Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) Emerging Markets Index, which represents a broad measure of equity market performance of emerging markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.0.09680.06320.04160.04080.160.13010.160.13010.00420.11720.00420.160.13010.0050<b>Fund Summary</b> <b>Government Fund</b><b>Investment Goal</b>0.01190.00970.00970.01660.02870.00970.01660.01870.0097-0.0020.00010.0159-0.003-0.00590.01660.00990.0067The primary goal of Government Fund is to provide as high a level of current income as is consistent, in the view of the Fund&#8217;s investment advisor, with safety of capital.As a secondary goal, the Fund seeks to reduce changes in its share price compared to longer term portfolios.You may qualify for discounts from the sales charge applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account - Buying Fund Shares&#8221; on page 72 of this Prospectus.0.10310.08230.0782500000.0710.0720.1020.0710.072<b>Fees and Expenses of the Fund</b>148127101780.09630.05530.0594A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.February 1, 20141.2949490439330243-0.0015Accordingly, the loss of money is a risk of investing in the Fund.857An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.773578422The following information provides some indication of the risks of investing in Developing World Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) Emerging Markets Index, which represents a broad measure of equity market performance of emerging markets.188817181288942Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.1-800-847-0200www.thornburg.comAfter-tax returns are calculated using the historical highest individual federal marginal income tax rates, and do not reflect state or local income taxes.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.0.00550.0027Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.Highest quarterly results2010-09-300.1817Lowest quarterly results2011-09-30-0.2317This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.59733010170990634712371215613<b>Fund Summary Global Opportunities Fund</b>21702605<b>Investment Goal</b><div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgDevelopingWorldFund column period compact * ~</div>
1373The Fund&#8217;s primary investment goal is long-term capital appreciation.0.178This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charge applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account - Buying Fund Shares&#8221; on page 72 of this Prospectus.0.17670.25410.2751This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types from issuers around the world.The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221; its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 129.49% of the average value of its portfolio.<b>Fees and Expenses of the Fund</b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:-0.41951010.04568000.3121<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 66.07% of the average value of its portfolio.0.136358<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgDevelopingWorldFund column period compact * ~</div>
279-0.1346<b>Principal Investment Strategies </b>The Fund pursues its investment goals by investing primarily in a broad range of equity securities, including common stocks, preferred stocks, real estate investment trusts, other equity trusts and partnership interests. The Fund may invest in any stock or other equity security which its investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;), believes may assist the Fund in pursuing its goals, including smaller companies with market capitalizations of less than $500 million. <br/><br/> The Fund may also invest in debt obligations of any kind, including corporate bonds, government obligations and other obligations. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics, such as convertible bonds. <br/><br/> The Fund portfolio includes investments in both domestic securities and securities of issuers domiciled outside the United States, including developing countries. Relative proportions of each will vary from time to time, depending upon the advisor&#8217;s view of specific investment opportunities and macro-economic factors. Under normal market conditions, the Fund invests a significant portion of its assets in issuers domiciled outside the United States. <br/><br/> The Fund&#8217;s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment, rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such security prior to the scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or otherwise to respond to market conditions.0.1518<b>Principal Investment Risks </b>635507An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests. <br/><br/> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility. <br/><br/> <b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position. <br/><br/> <b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries. <br/><br/> <b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments. <br/><br/> <b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk. <br/><br/> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates. <br/><br/> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund&#8217;s investments in developing countries. <br/><br/> <b>Real Estate Risk &#8211;</b> The Fund&#8217;s investments in real estate investment trusts (&#8220;REITs&#8221;) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT). <br/><br/> Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in Global Opportunities Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) All Country (AC) World Index, which represents a broad measure of both domestic and foreign equity market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares </b>1425Highest quarterly results for time period shown: 36.18%<br/> (quarter ended 6-30-09).<br/> Lowest quarterly results for time period shown: -26.80% <br/> (quarter ended 12-31-08).1162<b>Average Annual Total Returns</b> (periods ended<br/>12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.00.0100.1518<b>Invest<a name="prob442322_16"></a>ment Goal </b>0.14790.0984<b>Fund Summary</b> <b>Strategic Income Fund</b>0.00820.17320.1540.00820.1732<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgDevelopingWorldFund column period compact * ~</div>
0.00820.15740.1732The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 9.89% of the average value of its portfolio.<b>Fees and Exp<a name="prob442322_17"></a>enses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.0.00250.010-0.0291-0.0321You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.-0.0263-0.03692003-11-0150000-0.02722003-11-01-0.03692003-11-01-0.0246-0.0369<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgDevelopingWorldFund column period compact * ~</div>
A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.February 1, 20140.6607<b>Example.</b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.0.0993Accordingly, the loss of money is a risk of investing in the Fund.0.09360.0859The following information provides some indication of the risks of investing in Global Opportunities Fund by showing how the Fund&#8217;s investment results vary from year to year.0.07650.0161-0.0171The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) All Country (AC) World Index, which represents a broad measure of both domestic and foreign equity market performance.2300.07060.03790.0463Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.0.1248www.thornburg.com0.00787090.01040.0063121526051-800-847-0200The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.0.02510.0185After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.0.01290.0286Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.0.01450.03550.0593-0.03470.1645-0.00020.0634-0.0048-0.00360.05050.07420.01830.02380.0109<b>Portfolio Turnover.</b>0.045-0.50320The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 34.54% of the average value of its portfolio.0<b>Principal In<a name="prob442322_18"></a>vestment Strategies </b>0.44810.2726-0.02970.2187<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgDevelopingWorldFund column period compact * ~</div>
00.0100.07420.06230.04840.03890.1640.06170.16390.04660.10650.0440.16660.05180.19860.16660.22450.16660.04690.03230.03140.04410.04410.03646281113410.00670.00880.00490.00880.0045-0.02880.00880.0093-0.02880.0218-0.02880.00250.0100.00360.00390.00330.05490.05180.04550.00450.05610.00450.06940.00450.00110.00110.00110.0160.02380.013210048414232003-07-012003-07-012003-07-012007-02-012007-02-012005-02-010.0162005-02-012012-05-010.02382012-05-010.0110.32050.16870.08740.2430.182<b>Principal Invest<a name="prob442322_19"></a>ment Risks </b>14041466758-0.34652003-07-010.3660.13422520315117040.00490.1136<b>Past Perfo<a name="prob442322_20"></a>rmance of the Fund </b><b>Fund Summary Income Builder Fund</b>241-0.002284114663151You would pay the following expenses if you did not redeem your Class C shares:0.3073-0.15630.227You would pay the following expenses if you did not redeem your Class C shares:<b>Investment Goal</b><b>Fees and Expenses of the Fund</b><b>Shareholder Fees</b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of<br/>the value of your investment)<b>Example.</b><b>Portfolio Turnover. </b>0.1720.17150.11160.18220.20810.1822<b>Principal Investment Strategies</b>0.23340.1822<b>Principal Investment Risks</b><b>Shareholder Fees </b><br/>(fees paid directly from your investment)0.08990.07720.05180.09950.05180.11310.0518The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was take into account.605341112<b>Past Performance of the Fund</b><b>Annual Total Returns &#8211; Class A Shares </b><b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)The Fund&#8217;s primary investment goal is to provide a level of current income which exceeds the average yield on U.S. stocks generally, and which will generally grow, subject to periodic fluctuations, over the years on a per share basis.9327422007-02-013972007-02-01The Fund&#8217;s secondary investment goal is long-term capital appreciation.2007-02-012007-02-01<b>Example.</b>2007-02-012007-02-010.08962007-02-01This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.2007-02-01This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:1270This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:1282702<b>Portfolio Turnover.</b>You would pay the following expenses if you did not redeem your Class C shares:<b>Principal Investment Strategies</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 40.96% of the average value of its portfolio.Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio in pursuing the Fund&#8217;s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund&#8217;s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security before its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to market conditions.<br/><br/>Government Fund invests at least 80% of its assets in U.S. Government Securities. For this purpose, &#8220;U.S. Government Securities&#8221; means:<blockquote>Securities backed by the full faith and credit of the U.S. government, including direct obligations of the U.S. Treasury (such as U.S. Treasury Bonds) and obligations of U.S. government agencies and instrumentalities which are guaranteed by the U.S. Treasury (such as &#8220;Ginnie Mae&#8221; mortgage-backed certificates issued by the Government National Mortgage Association).<br/><br/>Securities issued or guaranteed by U.S. government agencies, instrumentalities or sponsored enterprises, but which are not backed by the full faith and credit of the U.S. government. These securities include mortgage-backed certificates, collateralized mortgage obligations (&#8220;CMOs&#8221;), and debentures issued by &#8220;Freddie Mac&#8221; (Federal Home Loan Mortgage Corporation) and &#8220;Fannie Mae&#8221; (Federal National Mortgage Association).</blockquote>U.S. Government Securities include for this purpose repurchase agreements secured by the securities described above, and participations having economic characteristics similar to those securities. &#8220;Participations&#8221; are undivided interests in pools of securities where the underlying credit support passes through to the participants.<br/><br/>Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life of normally less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.The Fund pursues its investment goals by investing in a broad range of income producing securities, primarily including stocks and bonds, as described below. The Fund will under normal conditions invest at least 80% of its assets in income-producing securities, and at least 50% of its assets in common stocks. <br /><br />The Fund may invest in any stock or other equity security which the investment advisor believes may assist the Fund in pursuing its investment goals (including smaller companies with market capitalization of less than $500 million and companies in developing countries), including preferred stock, publicly traded real estate investment trusts, other equity trusts and partnership interests. The Fund expects that equity investments in the Fund&#8217;s portfolio normally will be weighted in favor of companies which pay dividends or other current income. <br /><br />The Fund may invest in debt obligations of any kind, including corporate bonds and other obligations, mortgage- and other asset-backed securities and government obligations. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase. The Fund also may invest in debt obligations which have a combination of equity and debt characteristics, such as convertible bonds. <br /><br />The Fund may invest a significant portion of its assets in securities of issuers domiciled outside the United States, including developing countries. <br /><br />The Fund&#8217;s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or otherwise to respond to market conditions.<b>Principal Investment Risks</b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br /><br /><b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /><b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /><b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk.<br /><br /><b>High Yield Risk &#8211;</b> Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer&#8217;s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.<br /><br /><b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br /><br /><b>Prepayment Risk &#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /><b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries.<br /><br /><b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices.<br /><br /><b>Real Estate Risk &#8211;</b> The Fund&#8217;s investments in real estate investment trusts (&#8220;REITs&#8221;) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT). <br /><br />Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 65.226527161571<b>Investm<a name="prob442322_30"></a>ent Goal </b>The following information provides some indication of the risks of investing in Government Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3 and Class R5 share performance to the Barclays Intermediate Government Bond Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www. thornburg.com or by calling 1-800-847-0200.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.The Fund&#8217;s primary investment goal is to seek a high level of current income.The Fund&#8217;s secondary investment goal is some long-term capital appreciation.International Value Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)The secondary, non-fundamental goal of the Fund is to seek some current income.<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Fees and E<a name="prob442322_31"></a>xpenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.The Fund pursues its investment goals by investing in a broad range of income-producing investments from throughout the world, primarily including debt obligations and income-producing stocks. The Fund expects, under normal conditions, to invest a majority of its assets in the debt obligations described below, but the relative proportions of the Fund&#8217;s investments in debt obligations and in income producing stocks can be expected to vary over time. <br /><br /> The Fund may invest in debt obligations of any kind, of any quality, and of any maturity. The Fund expects, under normal conditions, to select a majority of its investments from among the following types of debt obligations: <ul type="square"><li style="margin-left:20px"> bonds and other debt obligations issued by domestic and foreign companies of any size (including lower-rated &#8220;high yield&#8221; or &#8220;junk&#8221; bonds)</li></ul> <ul type="square"><li style="margin-left:20px">mortgage-backed securities and other asset-backed securities </li></ul> <ul type="square"><li style="margin-left:20px">convertible debt obligations</li></ul> <ul type="square"><li style="margin-left:20px">obligations issued by foreign governments (including developing countries)</li></ul> <ul type="square"><li style="margin-left:20px"> collateralized mortgage obligations (&#8220;CMOs&#8221;), collateralized debt obligations (&#8220;CDOs&#8221;), collateralized bond obligations (&#8220;CBOs&#8221;), collateralized loan obligations (&#8220;CLOs&#8221;), and other structured finance arrangements </li></ul> <ul type="square"><li style="margin-left:20px"> obligations of the U.S. government and its agencies and sponsored enterprises </li></ul> <ul type="square"><li style="margin-left:20px"> other derivative instruments and structured notes </li></ul> <ul type="square"><li style="margin-left:20px"> zero coupon bonds and &#8220;stripped&#8221; securities </li></ul> <ul type="square"><li style="margin-left:20px"> taxable municipal obligations and participations in municipal obligations </li></ul> The Fund may invest in any stock or other equity security which the investment advisor believes may assist the Fund in pursuing its investment goals, including primarily income producing common and preferred stocks issued by domestic and foreign companies of any size (including smaller companies with market capitalizations of less than $500 million, and companies in developing countries), and also including publicly traded real estate investment trusts and other equity trusts and partnership interests. The Fund expects that its equity investments will be weighted in favor of companies that pay dividends or other current income. <br /><br /> The Fund&#8217;s investments are determined by individual issuer and industry analysis. Investment decisions are based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt and equity securities, and analysis of specific issuers. The Fund ordinarily acquires and holds debt obligations for investment rather than for realization of gains by short-term trading on market fluctuations. However, the Fund may dispose of any such investment prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or otherwise to respond to market conditions.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund. Please note that because the Fund&#8217;s objective is to provide high current income, the Fund invests with an emphasis on income, rather than stability of net asset value.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for mortgage- and other asset-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br /><br /> <b>Prepayment Risk &#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Credit Risk &#8211;</b> If obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those obligations may decline and the Fund&#8217;s share value and the dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated obligation, lower-rated and unrated obligations are generally more vulnerable than higher-rated obligations to default, to ratings downgrades, and to liquidity risk. Debt obligations backed by so-called &#8220;subprime&#8221; mortgages may also be subject to a greater risk of default or downgrade. Debt obligations issued by the U.S. government or its agencies, instrumentalities and government sponsored enterprises are also subject to credit risk. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. agencies, instrumentalities and enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the U.S. government, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk.<br /><br /> <b>High Yield Risk &#8211;</b> Debt obligations that are rated below investment grade and unrated obligations of similar credit quality (commonly referred to as &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) may have a substantial risk of loss. These obligations are generally considered to be speculative with respect to the issuer&#8217;s ability to pay interest and principal when due. These obligations may be subject to greater price volatility than investment grade obligations, and their prices may decline significantly in periods of general economic difficulty or in response to adverse publicity, changes in investor perceptions or other factors. These obligations may also be subject to greater liquidity risk.<br /><br /> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. This effect is typically more pronounced for lower-rated and unrated debt obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds), the value of which may fluctuate more significantly in response to poor economic growth or other changes in market conditions, political, economic and legal developments. The market value of any zero coupon bonds or &#8220;stripped&#8221; securities that the Fund may purchase will typically be more volatile than the value of a comparable, interest-paying bond. Additionally, zero coupon bonds and &#8220;stripped&#8221; securities are subject to the risk that the Fund may have to recognize income on its investment and make distributions to shareholders before it has received any cash payments on its investment.<br /><br /> <b>Risks Affecting Specific Issuers &#8211;</b> The value of a debt obligation or equity security may decline in response to developments affecting the specific issuer of the obligation or security, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. The market for lower-rated and unrated debt obligations (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) and debt obligations backed by so-called &#8220;subprime&#8221; mortgages may be less liquid than the market for other obligations, making it difficult for the Fund to value its investment in a lower-rated or unrated obligation or to sell the investment in a timely manner or at an acceptable price.<br /><br /> <b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /> <b>Foreign Investment Risk &#8211;</b> Investments in the equity securities or debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries. In addition, some foreign government debt obligations may be subject to default, delays in payment, adverse legislation or government action, or could be downgraded by ratings agencies.<br /><br /> <b>Structured Products Risk &#8211;</b> The Fund&#8217;s investments in structured finance arrangements, including CMOs, CDOs, CBOs and CLOs, involve the risks associated with the underlying pool of securities or other assets, and also may involve risks different or greater than the risks affecting the underlying assets. In particular, these investments may be less liquid than other debt obligations, making it difficult for the Fund to value its investment or sell the investment in a timely manner or at an acceptable price.<br /><br /> <b>Derivatives Risk &#8211;</b> The Fund&#8217;s investments in derivatives involve the risks associated with the securities or other assets underlying the derivatives, and also may involve risks different or greater than the risks affecting the underlying assets, including the inability or unwillingness of the other party to a derivative to perform its obligations to the Fund, the Fund&#8217;s inability or delays in selling or closing positions in derivatives, and difficulties in valuing derivatives.<br /><br /> <b>Real Estate Risk &#8211;</b> The Fund&#8217;s investments in real estate investment trusts (&#8220;REITs&#8221;) are subject to risks affecting real estate investments generally (including market conditions, competition, property obsolescence, changes in interest rates and casualty to real estate), as well as risks specifically affecting REITs (the quality and skill of REIT management and the internal expenses of the REIT). <br /><br /> Additional information about Fund investments, investment strategies and risks of investing in the Fund appears below beginning on page 38.The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total return for Class A shares would have varied in each full year shown. The average annual total return figures compare Class A share performance to the Barclays U.S. Universal Index, a broad measure of market performance, and to a Blended Benchmark comprised of 80% Barclays Aggregate Bond Index, which represents a broad measure of bond market performance, and 20% MSCI World Index, which represents a broad measure of equity market performance in developed markets. The returns reflected in the bar chart and in the table are for a class of shares that is not offered in this Prospectus but which would have substantially similar annual returns because the shares represent investments in the same portfolio of securities. Annual returns would differ only to the extent Class A shares are subject to a sales charge, but are subject to lower annual expenses before fee waivers and expense reimbursements than Class R3 shares, and higher annual expenses than Class R5 shares. Class R3 and Class R5 shares were first offered to investors on May 1, 2012, and Class A shares were first offered on December 19, 2007. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares</b><b>Shareholder Fees </b><br />(fees paid directly from your investment)Highest quarterly results for time period shown: 16.23%<br/>(quarter ended 6-30-09).<br/><br/>Lowest quarterly results for time period shown: -10.38%<br/> (quarter ended 12-31-08).<b>Annual Fund Operating Expenses </b><br />(expenses that you pay each year as a percentage of the value of your investment)<b>Average Annual Total Returns</b> (periods ended<br/> 12-31-12)<b>Example.</b><b>Average Annual Total Returns</b> (periods ended<br/>12-31-12)2009-12-162009-12-162009-12-162009-12-162009-12-162009-12-162009-12-162009-12-16241742127027160.0989This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds.<br /><br />The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund&#8217;s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund&#8217;s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk</b> <b>&#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Interest Rate Risk</b> <b>&#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value and dividends may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund&#8217;s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br/><br/><b>Prepayment Risk</b> <b>&#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Credit Risk</b> <b>&#8211;</b> All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund&#8217;s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government-sponsored enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund are rated &#8220;Aaa&#8221; by Moody&#8217;s Investors Services or &#8220;AA+&#8221; by Standard and Poor&#8217;s Corporation. Ratings agencies may reduce the ratings of any securities in the future.<br/><br/><b>Market and Economic Risk</b> <b>&#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.<br/><br/><b>Liquidity Risk</b> <b>&#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices.<br/><br/>Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 38.<br/><br/><b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 17.86% of the average value of its portfolio.<b>Principal Investm<a name="prob442322_32"></a>ent Strategies </b><b>Principal Invest<a name="prob442322_33"></a>ment Risks </b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.Accordingly, the loss of money is a risk of investing in the Fund.<b>Past Performance<a name="prob442322_34"></a> of the Fund </b><b>Past Performance of the Fund</b>0.3192<b>Annual Total Returns &#8211; Class R3 Shares </b>-0.48170000.45980.15330-0.0779000.2156After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares vary in each full year shown. The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the Morgan Stanley Capital International (MSCI) Europe, Australasia and Far East (EAFE) Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg. com or by calling 1-800-847-0200.<b>Average Annual Total Returns </b>(periods ended<br/> 12-31-12)<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgGlobalOpportunitiesFund column period compact * ~</div>
The Fund invests primarily in foreign securities or depository receipts of foreign securities. The Fund may invest in developing countries, but under normal conditions those investments are expected to comprise a smaller proportion of the Fund than investments in developed countries. <br /><br />The Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;), intends to invest on an opportunistic basis where the Fund&#8217;s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks classified as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies. <br /><br /> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund&#8217;s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are: <table style="font-size: pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">profitability </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">undervalued assets</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/book value ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry growth characteristics</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">franchise value</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">dividend characteristics </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">potential for favorable developments</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">security and consistency of revenues </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">EBIT <i>(earnings before interest and taxes)</i>/interest expense ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">EV (enterprise value)/EBITDA <i>(earnings before interest, taxes, depreciation and amortization) </i>ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table><br /> The Fund classifies its equity investments in the following three categories: <br /><br /><b> Basic Value: </b>Companies which, in Thornburg&#8217;s opinion, are financially sound with well established businesses selling at low valuations relative to the companies&#8217; net assets or potential earning power.<br /><br /><b> Consistent Earner:</b> Companies which normally exhibit steady earnings growth, cash flow characteristics and/or dividend growth. These companies may have above average profitability measures and normally sell at above average valuations. Emerging Franchise: Companies which, in Thornburg&#8217;s opinion, are in the process of establishing a leading position in a product, service or market with the potential to grow at an above average rate. Under normal conditions, the proportion of the Fund invested in this category will be lower than the other categories.<br /><br />Debt obligations may be considered for investment if Thornburg believes them to be more attractive than equity alternatives, or to manage risk. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase.0.00760.00760.00760.16110.1590.10460.16130.19640.16130.0050.22190.002500.1613The following information provides some indication of the risks of investing in Government Fund by showing how the Fund&#8217;s investment results vary from year to year.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgGlobalOpportunitiesFund column period compact * ~</div>
0.0040.0049The average annual total return figures compare Class R3 and Class R5 share performance to the Barclays Intermediate Government Bond Index, a broad measure of market performance.0.0041Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.-0.0136-0.0208-0.0161-0.0116-0.01210.0166-0.01160.00080.015-0.0116www. thornburg.com0.01171-800-847-0200-0.0031-0.0025-0.0018After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.0.01350.01250.00990.07060.06220.0560.02770.06980.02770.08370.0277<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgInternationalGrowthFund column period compact * ~</div>
The following information provides some indication of the risks of investing in Income Builder Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Standard &amp; Poor&#8217;s 500 Index, a broad measure of market performance, and to a Blended Benchmark comprised of 25% Barclays Capital Aggregate Bond Index, which represents a broad measure of bond market performance, and 75% MSCI World Index, which represents a broad measure of equity market performance in developed markets. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.Highest quarterly results for time period shown: 23.40% <br/>(quarter ended 6-30-09).<br/><br/>Lowest quarterly results for time period shown: -15.16% <br/>(quarter ended 12-31-08).0.1786Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.The following information provides some indication of the risks of investing in International Value Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class R3, Class R4, Class R5 and Class R6 share performance to the Morgan Stanley Capital International (MSCI) Europe, Australasia and Far East (EAFE) Index, a broad measure of market performance.<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgGlobalOpportunitiesFund column period compact * ~</div>
1-800-847-0200www.thornburg. comPast performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgInternationalGrowthFund column period compact * ~</div>
Highest quarterly results for time period shown: 22.73%<br />(quarter ended 6-30-09).<br /><br />Lowest quarterly results for time period shown: -20.95% (quarter ended 9-30-11).After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgGlobalOpportunitiesFund column period compact * ~</div>
The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Highest quarterly resultsActual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.2009-06-30<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgDevelopingWorldFundBarChart column period compact * ~</div>
0.234Lowest quarterly results2008-12-31-0.15160.4096Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.137The following information provides some indication of the risks of investing in Income Builder Fund by showing how the Fund&#8217;s investment results vary from year to year.127101The average annual total return figures compare Class A, Class C and Class I share performance to the Standard &amp; Poor&#8217;s 500 Index, a broad measure of market performance, and to a Blended Benchmark comprised of 25% Barclays Capital Aggregate Bond Index, which represents a broad measure of bond market performance, and 75% MSCI World Index, which represents a broad measure of equity market performance in developed markets.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.493450354www.thornburg.com1-800-847-0200The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgGlobalOpportunitiesFundBarChart column period compact * ~</div>
A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.873795626193917691404<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgInternationalGrowthFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgInternationalGrowthFund column period compact * ~</div>
2006-07-282006-07-282006-07-282006-07-282006-07-28-0.00072006-07-282006-07-282006-07-28An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br /><br /> <b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /> <b>Foreign Investment Risk &#8211; </b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries.<br /><br /> <b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /> <b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br /><br /> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. <br /><br /> Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 38.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgInternationalGrowthFundBarChart column period compact * ~</div>
The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgInternationalGrowthFund column period compact * ~</div>
0.10660.10660.160.06930.1080.160.11050.16-0.024-0.0258-0.02130.0166-0.02290.0166-0.02040.01660.04460.03990.03730.0615-0.0167<b>Fund Summary </b> <b>International Growth Fund</b>0.01970.03530.0452003-07-012003-07-012003-07-012003-07-012007-02-012007-02-012005-02-012005-02-01<b>Investment Goal </b>The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.<b>Fees and Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Annual Total Returns &#8211; Class R3 Shares </b>Highest quarterly results for time period shown: 3.46%<br/>(quarter ended 12-31-08).<br/><br/>Lowest quarterly results for time period shown: -2.42%<br/>(quarter ended 6-30-04).<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgGlobalOpportunitiesFund column period compact * ~</div>
<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:Highest quarterly results0.03462008-12-31Lowest quarterly results-0.02422004-06-30<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgInvestmentIncomeBuilderFund column period compact * ~</div>
<b>Fund Summary Value Fund</b><b>Investment Goal </b>The Fund seeks long-term capital appreciation by investing in equity and debt securities of all types.The secondary, non-fundamental goal of the Fund is to seek some current income.<b>Fees and Expenses of the Fund </b>00000.00380.00380.00500.00410.01290.0088-0.003-0.00210.00990.00670.0051016837926067946715301065<b>Annual Total Returns &#8211; Class A Shares </b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.The following information provides some indication of the risks of investing in Value Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class A shares have been different in each full year shown. The average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Standard &amp; Poor&#8217;s 500 Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg. com or by calling 1-800-847-0200.<b>Principal Investment Strategies</b><b>Principal Investment Risks</b><b>Average Annual Total Returns </b>(periods ended 12-31-12)Highest quarterly results for time period shown: 30.04%<br/>(quarter ended 6-30-09).<br/><br/>Lowest quarterly results for time period shown: -22.49%<br/>(quarter ended 9-30-11).0.01240.0113This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)0.033<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgInvestmentIncomeBuilderFund column period compact * ~</div>
<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)0.06730.067<b>Example.</b>This Example is intended to help you compare the cost of investing in Value Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:0.0387<b>Portfolio Turnover.</b>0.0344The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 54.16% of the average value of its portfolio.<b>Principal Investment Strategies </b>0.037The Fund expects to invest primarily in domestic equity securities (primarily common stocks) selected on a value basis. However, the Fund may own a variety of securities, including foreign equity securities, partnership interests and foreign and domestic debt obligations which, in the opinion of the Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;), offer prospects for meeting the Fund&#8217;s investment goals. <br /><br />Thornburg intends to invest on an opportunistic basis where the Fund&#8217;s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks classified as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies. <br /><br /> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund&#8217;s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are: <table style="font-size: pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">profitability </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">undervalued assets</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/book value ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry growth characteristics</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">franchise value</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">dividend characteristics </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">potential for favorable developments</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">security and consistency of revenues </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">EBIT (earnings before interest and taxes)/interest expense ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">EV (enterprise value)/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table> <br />The Fund classifies its equity investments in the following three categories:<br /><br /> <b> Basic Value: </b>Companies which, in Thornburg&#8217;s opinion, are financially sound with well established businesses selling at low valuations relative to the companies&#8217; net assets or potential earning power.<br /><br /> <b> Consistent Earner: </b> Companies which normally exhibit steady earnings growth, cash flow characteristics and/or dividend growth. These companies may have above average profitability measures and normally sell at above average valuations.<br /><br /> <b>Emerging Franchise:</b> Companies which, in Thornburg&#8217;s opinion, are in the process of establishing a leading position in a product, service or market with the potential to grow at an above average rate. Under normal conditions, the proportion of the Fund invested in this category will be lower than the other categories.<br /><br />The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars (which could include developing countries). <br/><br/> Debt obligations may be considered for investment if Thornburg believes them to be more attractive than equity alternatives, or to manage risk. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase. .0.0191<b>Principal Investment Risks </b>An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br/><br/><b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br/><br/><b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br/><br/><b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries.<br/><br/><b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br/><br/><b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. <br/><br/>Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 38.<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in Value Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3, Class R4 and Class R5 share performance to the Standard &amp; Poor&#8217;s 500 Composite Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg. com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class R3 Shares </b>You would pay the following expenses if you did not redeem your Class C shares:Highest quarterly results for time period shown: 30.07% <br/>(quarter ended 6-30-09). <br/><br/>Lowest quarterly results for time period shown: -22.51%<br/>(quarter ended 9-30-11).<b>Average Annual Total Returns</b> (periods ended<br/> 12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.<b>Portfolio Turnover.</b>0.01910.01030.0124The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 95.17% of the average value of its portfolio.0.01730.03910.02850.02730.04510.03370.0230.02250.0404<b>Principal Investment Strategies </b>0.2273Lowest quarterly results2011-09-30-0.2095Highest quarterly results2009-06-300.3004Lowest quarterly results2011-09-30-0.2249Highest quarterly results2009-06-300.5416Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.0.01940.0134The sales charge for Class A shares is not reflected in the returns shown in the bar chart above, and the returns would be less if the charge was taken into account.50000You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.The following information provides some indication of the risks of investing in Value Fund by showing how the Fund&#8217;s investment results vary from year to year.1-800-847-0200www.thornburg. comThe average annual total return figures compare Class A, Class B, Class C and Class I share performance to the Standard &amp; Poor&#8217;s 500 Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts not subject to federal income tax.After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class B, Class C and Class I shares because the returns of the classes are different.<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgInternationalValueFundClassR3R4R5R6 column period compact * ~</div>
February 1, 2014An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.Accordingly, the loss of money is a risk of investing in the Fund.The following information provides some indication of the risks of investing in Value Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class R3, Class R4 and Class R5 share performance to the Standard &amp; Poor&#8217;s 500 Composite Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg. com<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgInternationalValueFundClassR3R4R5R6 column period compact * ~</div>
The Fund expects to invest primarily in equity securities from issuers around the world (primarily common stocks) selected for their growth potential and, under normal market conditions, invests at least 75% of its assets in foreign securities or depository receipts of foreign securities. However, the Fund may own a variety of securities, including domestic equity securities and partnership interests. The Fund may invest in developing countries and in smaller companies with market capitalizations of less than $500 million.<br/><br/>The Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) intends to invest in companies that it believes will have growing revenues and earnings. The Fund can invest in companies of any size, from larger, well-established companies to smaller, emerging growth companies.<br/><br/> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are: <table style="font-size: pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">price/revenue ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">business model </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">PE/growth rate ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">industry growth potential </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">enterprise value/EBITDAratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">asset appreciation potential </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">management strength</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">potential size of business </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">value based on earnings growth discount model </td> <td>&nbsp;</td> <td align="left" valign="top"><b></b> </td> <td>&nbsp;</td> <td align="left" valign="top"></td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table> <br/>The Fund typically makes equity investments in the following three types of companies:<br/><br/><b>Growth Industry Leaders</b> are growing companies that appear to have proprietary advantages in industry segments that Thornburg expects to grow faster than the overall market. Stocks of these companies generally sell at premium valuations (relative to the MSCI All Country World ex-U.S. Growth Index).<br /><br /> <b>Consistent Growth</b> companies. Stocks in this category generally sell at premium valuations (relative to the MSCI All Country World ex-U.S. Growth Index) and tend to show earnings or cash flow growth, or both. There are no assurances that these trends will continue in the future.<br /><br /> <b>Emerging Growth</b> companies are typically growing companies that in Thornburg&#8217;s opinion are in the process of establishing a leading position in a significant product, service or market and which Thornburg expects will grow, or continue to grow, at a rate exceeding the growth of the world&#8217;s gross domestic product (&#8220;GDP&#8221;). These companies may not be profitable at the time of purchase. <br /><br /> In conjunction with individual issuer analysis, Thornburg may identify economic sectors it expects to experience growth. At times this approach may produce a focus on certain industries, such as technology, financial services, healthcare or biotechnology. The exposure to particular economic sectors or industries likely will vary over time. Investment decisions are also based on domestic and international economic developments, outlooks for securities markets, interest rates and inflation, and the supply and demand for debt and equity securities. <br /><br /> Debt obligations, usually with associated equity features, occasionally will be considered for investment when Thornburg believes them to be more attractive than equity alternatives. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase.1-800-847-0200<b>Principal Investment Risks </b>After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgInvestmentIncomeBuilderFund column period compact * ~</div>
Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.2003-07-012003-07-012003-07-012003-07-012012-05-012012-05-01An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br /><br /> <b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br /><br /> <b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries because the economies of those countries are usually less diversified, communications, transportation and economic infrastructures are less developed, and developing countries ordinarily have less established legal, political, business and social frameworks. At times the prices of equity securities or debt obligations of a developing country issuer may be extremely volatile. An issuer domiciled in a developed country may be similarly affected by these developing country risks to the extent that the issuer conducts a significant percentage of its business in developing countries.<br /><br /> <b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br /><br /> <b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br /><br /> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. This risk may be more pronounced for the Fund&#8217;s investments in developing countries. <br /><br /> Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in International Growth Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total return for Class A shares has been different in each full year shown. The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) All Country (AC) World ex-U.S. Growth Index, a market capitalization weighted index which includes growth companies in developed and emerging markets throughout the world, excluding the United States. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www. thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class A Shares </b><div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgInternationalValueFundClassR3R4R5R6 column period compact * ~</div>
Highest quarterly results for time period shown: 28.24% <br/>(quarter ended 6-30-09). <br/><br/>Lowest quarterly results for time period shown:-25.74% <br/>(quarter ended 12-31-08).A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.<b>Average Annual Total Returns </b> (periods ended<br/>12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts not subject to federal income tax. The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgInternationalValueFundClassR3R4R5R6BarChart column period compact * ~</div>
500000.0725You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.0.0952February 1, 20140.21860.0608-0.41570.45120.0913-0.135<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgInternationalValueFundClassR3R4R5R6 column period compact * ~</div>
0.1066<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgLimitedTermU.S.GovernmentFundClassR3R5 column period compact * ~</div>
<b>Average Annual Total Returns </b>(periods ended <br/>12-31-12)<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleNoRedemptionTransposedThornburgInvestmentIncomeBuilderFund column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgInvestmentIncomeBuilderFundBarChart column period compact * ~</div>
<b>Fund Summary Income Fund</b><b>Investment Goal </b>The primary goal of Income Fund is to provide as high a level of current income as is consistent, in the view of the Fund&#8217;s investment advisor, with safety of capital.As a secondary goal, the Fund seeks to reduce changes in its share prices compared to longer term portfolios.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares varies from day to day and over time,and when you sell your shares they may be worth less than what you paid for them. The following is a summary of the principal risks of investing in the Fund.<br/><br/><b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br/><br/><b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. The value of a security may change in response to developments affecting entire economies, markets or industries, including changes in interest rates, political and legal developments, and general market volatility.<br/><br/><b>Risks Affecting Specific Issuers &#8211;</b> The value of an equity security or debt obligation may decline in response to developments affecting the specific issuer of the security or obligation, even if the overall industry or economy is unaffected. These developments may include a variety of factors, including but not limited to management issues or other corporate disruption, a decline in revenues or profitability, an increase in costs, or an adverse effect on the issuer&#8217;s competitive position.<br/><br/><b>Smaller Company Risk &#8211;</b> Investments in smaller companies may involve additional risks because of limited product lines, limited access to markets and financial resources, greater vulnerability to competition and changes in markets, lack of management depth, increased volatility in share price, and possible difficulties in valuing or selling the investments.<br/><br/><b>Foreign Investment Risk &#8211;</b> Investments in securities of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection. These risks may be more pronounced for investments in developing countries.<br/><br/><b>Credit Risk &#8211;</b> If debt obligations held by the Fund are downgraded by ratings agencies or go into default, or if management action, legislation or other government action reduces the ability of issuers to pay principal and interest when due, the value of those debt obligations may decline and the Fund&#8217;s share value and any dividends paid by the Fund may be reduced. Because the ability of an issuer of a lower-rated or unrated debt obligation (including particularly &#8220;junk&#8221; or &#8220;high yield&#8221; bonds) to pay principal and interest when due is typically less certain than for an issuer of a higher-rated debt obligation, lower-rated and unrated debt obligations are generally more vulnerable than higher-rated debt obligations to default, to ratings downgrades, and to liquidity risk.<br/><br/><b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments in debt obligations may decline and the Fund&#8217;s share value may be reduced. This effect is typically more pronounced for intermediate and longer-term debt obligations. Decreases in market interest rates may result in prepayments of debt obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br/><br/><b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the investments promptly, or may only be able to sell investments at less than desired prices. <br/><br/>Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 65.<b>Fund Summary International Value Fund</b><div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgInvestmentIncomeBuilderFund column period compact * ~</div>
-0.2682008-12-31Lowest quarterly results0.36182009-06-30Highest quarterly resultsYou may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.50000A 1.00% contingent deferred sales charge (CDSC) is imposed on redemptions of any part or all of a purchase of $1 million or more within 12 months of purchase.February 1, 2014<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgValueFundClassR3R4R5 column period compact * ~</div>
0.9517Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other governmental agency.The following information provides some indication of the risks of investing in International Growth Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class A, Class C and Class I share performance to the Morgan Stanley Capital International (MSCI) All Country (AC) World ex-U.S. Growth Index, a market capitalization weighted index which includes growth companies in developed and emerging markets throughout the world, excluding the United States.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www. thornburg.com1-800-847-0200February 1, 20140.3454Other expenses are estimated for the current fiscal year.The sales charge for Class A shares is not reflected in the returns shown on the bar chart, and the returns would be less if the charge was taken into account.Accordingly, the loss of money is a risk of investing in the Fund.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgValueFundClassR3R4R5 column period compact * ~</div>
After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.The Fund expects to invest primarily in domestic equity securities (primarily common stocks) selected on a value basis. However, the Fund may own a variety of securities, including foreign equity securities, partnership interests and foreign and domestic debt obligations which, in the opinion of the Fund&#8217;s investment advisor, Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;), offer prospects for meeting the Fund&#8217;s investment goals. <br/><br/>Thornburg intends to invest on an opportunistic basis where the Fund&#8217;s portfolio managers believe intrinsic value is not recognized by the marketplace. The Fund seeks to identify value in a broad or different context by investing in a diversified portfolio of stocks classified as basic values, consistent earners, and emerging franchises, when the portfolio managers believe these issues are value priced. The relative proportions of securities invested in each of those categories will vary over time. The Fund seeks to invest in promising companies, and may invest in stocks that reflect unfavorable market perceptions of the company or industry fundamentals. The Fund may invest in companies of any size, but invests primarily in the large and middle capitalization range of publicly traded companies. <br /><br /> Thornburg primarily uses individual issuer and industry analysis to make investment decisions. Value, for purposes of the Fund&#8217;s selection criteria, may consider both current and projected measures. Among the specific factors considered by Thornburg in identifying securities for inclusion in the Fund are: <table style="font-size: pt" cellspacing="0" border="0" cellpadding="0" width="100%"> <tr valign="bottom"> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="1%">&nbsp;</td> <td width="2%">&nbsp;</td> <td width="45%">&nbsp;</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">profitability </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">undervalued assets</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/earnings ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">earnings growth potential</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/book value ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry growth characteristics</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">price/cash flow ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">industry leadership</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">debt/capital ratio </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">franchise value</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">dividend characteristics </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">potential for favorable developments</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">security and consistency of revenues </td> <td>&nbsp;</td> <td align="left" valign="top"><b>&#9632;</b> </td> <td>&nbsp;</td> <td align="left" valign="top">EBIT (earnings before interest and <br /> taxes)/interest expense ratio</td> </tr> <tr valign="bottom"> <td valign="top"><div style="margin-left:0px; text-indent:-0px"><b>&#9632;</b> </div></td> <td>&nbsp;</td> <td align="left" valign="top">EV (enterprise value)/EBITDA (earnings before interest, taxes, depreciation and amortization) ratio</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> <td>&nbsp;</td> <td align="left" valign="top">&nbsp;</td> </tr> </table> <br />The Fund classifies its equity investments in the following three categories:<br /><br /> <b> Basic Value: </b>Companies which, in Thornburg&#8217;s opinion, are financially sound with well established businesses selling at low valuations relative to the companies&#8217; net assets or potential earning power.<br /><br /> <b> Consistent Earner: </b> Companies which normally exhibit steady earnings growth, cash flow characteristics and/or dividend growth. These companies may have above average profitability measures and normally sell at above average valuations.<br /><br /> <b>Emerging Franchise:</b> Companies which, in Thornburg&#8217;s opinion, are in the process of establishing a leading position in a product, service or market with the potential to grow at an above average rate. Under normal conditions, the proportion of the Fund invested in this category will be lower than the other categories.<br/><br/>The Fund selects foreign securities issued by companies domiciled in countries whose currencies are freely convertible into U.S. dollars, or in companies in other countries whose business is conducted primarily in U.S. dollars (which could include developing countries). <br /><br />Debt obligations may be considered for investment if Thornburg believes them to be more attractive than equity alternatives, or to manage risk. The Fund may purchase debt obligations of any maturity and of any credit quality. There is no minimum credit quality or rating of debt obligation the Fund may purchase.The following information provides some indication of the risks of investing in Strategic Income Fund by showing how the Fund&#8217;s investment results vary from year to year.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts not subject to federal income tax.The average annual total return figures compare Class A share performance to the Barclays U.S. Universal Index, a broad measure of market performance, and to a Blended Benchmark comprised of 80% Barclays Aggregate Bond Index, which represents a broad measure of bond market performance, and 20% MSCI World Index, which represents a broad measure of equity market performance in developed markets.The after-tax returns shown relate only to Class A shares, and after-tax returns will vary for Class C and Class I shares because the returns of the classes are different.Highest quarterly resultsPast performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.2009-06-30www.thornburg.com0.28241-800-847-0200Lowest quarterly resultsAfter-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.2008-12-31Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. Actual after-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.-0.257400<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgValueFundClassR3R4R5 column period compact * ~</div>
00<b>Fees and Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.0.00750.00750.00500.00470.00440.00020.0002<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgValueFundClassR3R4R5BarChart column period compact * ~</div>
<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example.</b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 23.72% of the average value of its portfolio.<b>Principal Investment Strategies </b>Thornburg Investment Management, Inc. (&#8220;Thornburg&#8221;) actively manages the Fund&#8217;s portfolio in pursuing the Fund&#8217;s investment goals. While Thornburg follows domestic and international economic developments, outlooks for securities markets, interest rates and inflation, the supply and demand for debt obligations, and other factors, the Fund&#8217;s investments are determined by individual security analysis. The Fund ordinarily acquires and holds securities for investment rather than for realization of gains by short-term trading on market fluctuations. However, it may dispose of any security prior to its scheduled maturity to enhance income or reduce loss, to change the portfolio&#8217;s average maturity, or to otherwise respond to current market conditions. <br /><br /> The Fund invests at least 65% of its net assets in (i) obligations of the U.S. government, its agencies and instrumentalities, and (ii) debt obligations rated at the time of purchase in one of the three highest ratings of Standard &amp; Poor&#8217;s Corporation (AAA, AA or A) or Moody&#8217;s Investors Services, Inc. (Aaa, Aa or A) or, if no credit rating is available, judged to be of comparable quality by Thornburg. The Fund will not invest in any debt obligation rated at the time of purchase lower than BBB by Standard &amp; Poor&#8217;s or Baa by Moody&#8217;s or of equivalent quality as determined by Thornburg. The Fund may purchase debt obligations such as corporate debt obligations, mortgage-backed securities, other asset-backed securities, municipal securities, and commercial paper and bankers&#8217; acceptances. The Fund may purchase foreign securities of the same types and quality as the domestic securities it purchases when Thornburg anticipates foreign securities offer more investment potential. <br /><br /> Because the magnitude of changes in the value of interest-bearing obligations is greater for obligations with longer terms, the Fund seeks to reduce changes in its share value by maintaining a portfolio of investments with a dollar-weighted average maturity or expected life normally of less than five years. There is no limitation on the maturity of any specific security the Fund may purchase, and the Fund may sell any security before it matures. The Fund also attempts to reduce changes in share value through credit analysis, selection and diversification.<b>Principal Investment Risks </b>Although the Fund may acquire obligations issued or guaranteed by the U.S. government and its agencies, instrumentalities and enterprises, neither the Fund&#8217;s net asset value nor its dividends are guaranteed by the U.S. government. An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. Accordingly, the loss of money is a risk of investing in the Fund. The value of the Fund&#8217;s shares and its dividends may fluctuate from day to day and over time, and when you sell your shares they may be worth less than what you paid for them. If your sole objective is preservation of capital, then the Fund may not be suitable for you because the Fund&#8217;s share value will fluctuate, including as interest rates change. Investors whose sole objective is preservation of capital may wish to consider a high quality money market fund. The following is a summary of the principal risks of investing in the Fund.<br /><br /> <b>Management Risk &#8211;</b> The Fund is an actively managed portfolio, and the value of the Fund may be reduced if Thornburg pursues unsuccessful investments or fails to correctly identify risks affecting the broad economy or specific issuers in which the Fund invests.<br /><br /> <b>Interest Rate Risk &#8211;</b> When interest rates increase, the value of the Fund&#8217;s investments may decline and the Fund&#8217;s share value and dividends may be reduced. This effect is typically more pronounced for intermediate and longer-term obligations. This effect is also typically more pronounced for the Fund&#8217;s investment in mortgage-backed securities, the value of which may fluctuate more significantly in response to interest rate changes. When interest rates decrease, the Fund&#8217;s dividends may decline.<br /><br /> <b>Prepayment Risk &#8211;</b> Decreases in market interest rates may result in prepayments of obligations the Fund acquires, requiring the Fund to reinvest at lower interest rates.<br /><br /> <b>Credit Risk &#8211;</b> All securities owned by the Fund may be subject to default, delays in payment, adverse legislation or other government action, or could be downgraded by ratings agencies, reducing the value of the Fund&#8217;s shares. Securities backed by the full faith and credit of the U.S. government, such as U.S. Treasury obligations, are commonly regarded as having small exposure to credit risk. Obligations of certain U.S. government agencies, instrumentalities and government sponsored enterprises (sometimes referred to as &#8220;agency obligations&#8221;) are not direct obligations of the United States, may not be backed by the full faith and credit of the U.S. government, and may have a greater exposure to credit risk. Although the U.S. government is required by law to provide credit support for some agency obligations, there is no assurance that the U.S. government would provide financial support for any such obligation on a default by the issuing agency, instrumentality or enterprise in the absence of a legal requirement to do so. As of the date of this Prospectus, securities backed by the full faith and credit of the U.S. government, and securities of U.S. government agencies, instrumentalities and enterprises which may be purchased by the Fund, are rated &#8220;Aaa&#8221; by Moody&#8217;s Investors Services or &#8220;AA+&#8221; by Standard and Poor&#8217;s Corporation. Ratings agencies may reduce the ratings of any securities in the future. Lower-rated or unrated obligations held by the Fund may have, or may be perceived to have, greater risk of default and ratings downgrades.<br /><br /> <b>Market and Economic Risk &#8211;</b> The value of the Fund&#8217;s investments may decline and its share value may be reduced due to changes in general economic and market conditions. For example, a fall in worldwide demand for U.S. government securities or general economic decline could lower the value of those securities.<br /><br /> <b>Foreign Investment Risk &#8211;</b> Investments in the debt obligations of foreign issuers may involve risks including adverse fluctuations in currency exchange rates, political instability, confiscations, taxes or restrictions on currency exchange, difficulty in selling foreign investments, and reduced legal protection.<br /><br /> <b>Liquidity Risk &#8211;</b> Due to a lack of demand in the marketplace or other factors, the Fund may not be able to sell some or all of the obligations promptly, or may only be able to sell obligations at less than desired prices. <br /><br /> Additional information about Fund investments, investment strategies, and risks of investing in the Fund appears below beginning on page 38.<b>Past Performance of the Fund </b>The following information provides some indication of the risks of investing in Income Fund by showing how the Fund&#8217;s investment results vary from year to year. The bar chart shows how the annual total returns for Class R3 shares have been different in each full year shown. The average annual total return figures compare Class R3 and Class R5 share performance to the Barclays Intermediate Government/ Credit Bond Index, a broad measure of market performance. Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future. The performance information shown below is as of the calendar year ended December 31, 2012. Updated performance information may be obtained on the Thornburg website at www.thornburg.com or by calling 1-800-847-0200.<b>Annual Total Returns &#8211; Class R3 Shares </b>Highest quarterly results for time period shown: 6.67% <br />(quarter ended 6-30-09). <br /><br />Lowest quarterly results for time period shown: -2.73% <br />(quarter ended 9-30-08).<b>Average Annual Total Returns</b> (periods ended<br/>12-31-12)After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes. Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.<div style="display:none">~ http://www.thornburg.com/role/ScheduleShareholderFeesThornburgLimitedTermIncomeFundClassR3R5 column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualFundOperatingExpensesThornburgLimitedTermIncomeFundClassR3R5 column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgLimitedTermIncomeFundClassR3R5 column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgLimitedTermIncomeFundClassR3R5BarChart column period compact * ~</div>
<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgLimitedTermIncomeFundClassR3R5 column period compact * ~</div>
0.2372February 1, 2014Other expenses are estimated for the current fiscal year.An investment in the Fund is not a deposit in any bank and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.Accordingly, the loss of money is a risk of investing in the Fund.The following information provides some indication of the risks of investing in Income Fund by showing how the Fund&#8217;s investment results vary from year to year.The average annual total return figures compare Class R3 and Class R5 share performance to the Barclays Intermediate Government/ Credit Bond Index, a broad measure of market performance.Past performance (before and after taxes) is not necessarily an indication of how the Fund will perform in the future.www.thornburg.com1-800-847-0200Highest quarterly results2009-06-300.0667-0.0015Lowest quarterly results-0.002-0.00072008-09-30-0.0273000000After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect state or local income taxes.Actual after-tax returns depend on an investor&#8217;s own tax situation and may differ from the returns shown. After-tax returns are not relevant to persons or accounts (such as qualified retirement plans) not subject to federal income tax.0.008600.0046<div style="display:none">~ http://www.thornburg.com/role/ScheduleAverageAnnualTotalReturnsTransposedThornburgValueFundClassR3R4R5 column period compact * ~</div>
0.0132-0.0033Highest quarterly results2009-06-300.30072011-09-30-0.2251Lowest quarterly results0.00990.5416<b>Past Performance of the Fund</b>000000000.00880.00880.00880.00880.0050.002500<div style="display:none">~ http://www.thornburg.com/role/ScheduleExpenseExampleTransposedThornburgLimitedTermU.S.GovernmentFundClassR3R5 column period compact * ~</div>
0.01110.0110.0041<b>Explanation of Acquired Fund Fees and Expenses.</b><br/>&#8220;Acquired Fund Fees and Expenses&#8221; shown in the Annual Fund Operating Expenses table in the left-hand column are expenses incurred indirectly by other investment companies, such as business development companies, in which the Fund may hold shares. These operating expenses are similar to the expenses paid by other businesses owned by the Fund, are not direct costs paid by Fund shareholders, and are not used to calculate the Fund&#8217;s net asset value. These expenses have no impact on the costs associated with Fund operations. Regulatory rules require that the Acquired Fund Fees and Expenses be added to the actual operating expenses of the Fund, and that the total be shown in the bottom line of the Annual Fund Operating Expenses table in the left-hand column. Please see the expense figures shown in the Financial Highlights for the Fund, at pages 118 &#8211; 119, for a clearer picture of the Fund&#8217;s actual operating costs.0.02490.02230.01290.0099<b>Fund Summary Value Fund</b>-0.0099-0.0083-0.003-0.001<div style="display:none">~ http://www.thornburg.com/role/ScheduleAnnualTotalReturnsThornburgLimitedTermU.S.GovernmentFundClassR3R5BarChart column period compact * ~</div>
0.0150.0140.00990.00890.001115314310191681617379305<b>Explanation of Acquired Fund Fees and Expenses. </b>&#8220;Acquired Fund Fees and Expenses&#8221; shown in the table in the left-hand column are expenses incurred indirectly by other investment companies, such as business development companies, in which the Fund may hold shares. These operating expenses are similar to the expenses paid by other businesses owned by the Fund, are not direct costs paid by Fund shareholders, and are not used to calculate the Fund&#8217;s net asset value. These expenses have no impact on the costs associated with Fund operations. Regulatory rules require that the Acquired Fund Fees and Expenses be added to the actual operating expenses of the Fund, and that the total be shown in the bottom line of the Annual Fund Operating Expenses table in the left-hand column. Please see the expense figures shown in the Financial Highlights for the Fund, at pages 116 &#8211; 117, for a clearer picture of the Fund&#8217;s actual operating costs.1236111967953727512500153012040.44980.2746-0.03050.21880.21880.21870.14220.16660.21940.16660.22480.16660.22480.16660.00860.00860.03890.03650.0317-0.0120.0398-0.0120.044-0.0120.0050.0440.0025-0.0120.00440.00670.0180.0178-0.003-0.00380.0150.014<b>Shareholder Fees </b><br/>(fees paid directly from your investment)<b>Annual Fund Operating Expenses </b><br/>(expenses that you pay each year as a percentage of the value of your investment)This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund. You may qualify for discounts from the sales charges applicable to Class A shares if you or other qualifying account holders invest, or agree to invest in the future, at least $50,000 in the Thornburg Funds. More information about these and other discounts is available from your financial professional and in &#8220;Opening Your Account &#8211; Buying Fund Shares&#8221; on page 72 of this Prospectus.<b>Explanation of Acquired Fund Fees and Expenses. </b><br/>&#8220;Acquired Fund Fees and Expenses&#8221; shown in the Annual Fund Operating Expenses table in the left-hand column are expenses incurred indirectly by other investment companies, such as business development companies, in which the Fund may hold shares. These operating expenses are similar to the expenses paid by other businesses owned by the Fund, are not direct costs paid by Fund shareholders, and are not used to calculate the Fund&#8217;s net asset value. These expenses have no impact on the costs associated with Fund operations. Regulatory rules require that the Acquired Fund Fees and Expenses be added to the actual operating expenses of the Fund, and that the total be shown in the bottom line of the Annual Fund Operating Expenses table in the left-hand column. Please see the expense figures shown in the Financial Highlights for the Fund, at pages 106 &#8211; 107, for a clearer picture of the Fund&#8217;s actual operating costs.15314310153752338694792969220910.0174206315610.0121-0.0047-0.0020.01270.01011291035023640.15030.22199006460.1798<b>Inve<a name="prob442322_44"></a>stment Goal </b>20130.11291448The Fund seeks long-term growth of capital by investing in equity securities selected for their growth potential.<b>Fees an<a name="prob442322_45"></a>d Expenses of the Fund </b>-0.51This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.0.45390.098<b>Example.</b>0.01280.2136<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221;) its portfolio. A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal year, the Fund&#8217;s portfolio turnover rate was 95.17% of the average value of its portfolio.<b>Principal Inv<a name="prob442322_46"></a>estment Strategies </b><b>Principal <a name="prob442322_47"></a>Investment Risks </b><b>Past Pe<a name="prob442322_48"></a>rformance of the Fund </b><b>Annual Total Returns &#8211; Class R3 Shares </b>0.21360.21360.13880.1521-0.0079-0.0079-0.00670.03150.07740.07720.06840.06590.07460.05060.21480.15210.04920.21970.05540.15210.066-0.00690.0315-0.00290.03150.0030.04030.04880.0541This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.<b>Fund Summary</b> <b>Developing World Fund</b><b>Investment Goal </b>0.07190.04450.04520.06190.0485<b>Fees and Expenses of the Fund </b>This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.<b>Shareholder Fees </b><br/>(fees paid directly from your investment)0.07570.04840.04860.06230.0498<b>Annual Fund Operating Expenses</b><br/>(expenses that you pay each year as a percentage of the value of your investment)<b>Example. </b>This Example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. <br/><br/>The Example assumes that you invest $10,000 in the Fund for the time periods indicated and then redeem all of your shares at the end of those periods. The Example also assumes that your investment has a 5% return each year, dividends and distributions are reinvested, and that the Fund&#8217;s operating expenses remain the same. Although your actual costs may be higher or lower, based on these assumptions (and giving effect to fee waivers and expense reimbursements in the first year), your costs would be:<b>Portfolio Turnover.</b>The Fund pays transaction costs, such as commissions, when it buys and sells securities (or &#8220;turns over&#8221; its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in Annual Fund Operating Expenses or in the Example, affect the Fund&#8217;s performance. During the most recent fiscal